RELISHED IN NEW YORK. 1834 ESTABLISHED IN SAN FRANCISCO, 1855 ILLUSTRATED CATALOGUE AND MANUAL OF CIVIL ENGINEERS' AND PURVEYORS' INSTRUMENTS:; (With Useful Tables, Illustrations and Descriptions of the Latest Improvements on the Most Recent Instruments of Precision.) MANUFACTURED BY J. C. SAhA SUCCESSOR TO JOHN ROBCH 429 MONTGOMERY ST., Cor. Sacramento ~ SAN 1 1896 fy PRICE, FIFTY CENTS TF^TIMOMIAI LIBRARY OF THE UNIVERSITY OF CALIFORNIA. OIKT OF" Received Accession No. 3/ - Class No. sir*} SillCC 1865, tJlC TTfcchanics' institute of tSan Francisco //us awarded me 8 Gold Medals 4 Grand Silver Medals 1 Grand Bronze Medal 8 Silver Medals and 6 Diplomas for the best Surveying' and l^iginccrhi^ Instruments^ Altitude Barometers and Drawing Instruments. I also received 3 Gold Medals and 1 Diploma of Honor at the California Sntcrnationai TTfidiuintcr Exposition, There arc on file in mv office, hundreds of unsolic- ited testimonials which all parties i tit crested in such matters arc free to read at anv time. OSTABLISHED ,N NEW YORK, 1X11 ESTABLISHED ,N S AN FRANC.SCO, 1S55 ILLUSTRATED CATALOGUE AND MANUAL OF CIVIL ENGINEERS' AND SURVEYORS' INSTRUMENTS (With Useful Tables, Illustrations and Descriptions of the Latest Improvements on the Most Recent Instruments of Precision.) MANUFACTURED BY J. C. SAhA SUCCESSOR TO CH 429 MONTGOrvTBe^ST., Cor. Sacramento SAN FRANCISCO, CAL. 1896 PRICE, FIFTY CENTS SUBDIVISIONS / Introduction, ... (> Preface, Part A Surveyors' and Engineers' Instruments for Field Work, ... 23 Part B Surveyors' Engineers' Architects' and Draughtsmen's Office Requisites, . ( .M Part C Miscellaneous Scientific Instruments, 101 Part D Papers and Tables, . . 107 J. C. 429 Montgomery Street, San Francisco, Cal. TO CORRESPONDENTS This catalog-lit' and price Us! supersedes all former editions. The prices hi this catalogue are net cash, and instruments are not sold on the installment plan. Every instrument is carefully packed, and the responsibility of the house ceases when instruments leave the factory. In case of damage, the express companies must be held liable. Instruments are not sent on trial but will be sent (\ (). /). for pur- poses of examination. Goods sent C. O. D. only when order is accompanied bv a deposit sufficient to pay expressage both ways. 7 he engravings in this catalogue give a good idea of the instru- ments at the present time; as improvements however, are being constantly made, customers will always receive the latest improved instruments. Mv aluminum instruments weigh from jo to 50% less than the reg- ular ones, and the price is 15% higher. II 'eight of regular instruments are as follows: Transits, No.... 1 2 3 4 5 6 7 14^ Ibs. 15 16 17 11 10 17 '4 Tripods ...8K M sy 2 8^ 7 7 8'< Levels ...8 Ibs. 9 10 11 15 12|< 10 8 Tripods ... 8>< 8^ 8 ' 4 8 Any extras to transits and levels supplied at the lowest rates. The illustrations of transits, levels and other surveying instruments in this catalogue, represent instruments made exclusively in my shop. Standard astronomical instruments and other instruments not illus- trated in this catalogue, are kept in stock and can be furnished upon application. Having made arrangements with foreign makers of such instruments, I can supply them upon the most reasonable terms. INTRODUCTION In addition to the long personal experience, indispen- sable to the manufacturer, and the trained staff of work- men engaged in the delicate task of building surveying and engineering instruments, and automatic machinery of precision, it is absolutely necessary to build such instruments so as to conform with the mathematical exactions required to perform correct work in the field and office. The following illustrations will give an idea of the most prominent o?ies amongst those in use in my well-supplied workshop. i PREFACE WHEN JOHN ROACH, the founder of this house, commenced business in New York City in 1834, the American Transit was only three years old. Proper castings were difficult to obtain, and the instrument-maker at that time worked under many disadvantages. There were no lenses made in the United States suitable for surveying instruments, and until about 1850, when an instrument was ordered, the telescope had to be made to suit the glasses obtainable. About the latter date, good glasses of American make commenced to appear, and there was a noticeable improvement in the making of transits; some- thing like uniformity in size and make was obtainable. In 1855 Mr. Roach established himself in San Francisco, and the ( ' Roach Instruments ' ' became known in the West wherever the sur- veyor pitched his camp. Some of the first made are in use to this day and there is no sign of breaking down yet; they have naturally an aged appearance, but their joints are in fairly good order, their graduations clear, and the glasses nearly perfect. Instruments in the early days were not handled always by the most competent men and received harder usage than modern instru- ments are called upon to stand; as a consequence, metal was not spared in their construction. While lightness was always a desideratum, still strength was more important, and the early instruments were strong. They had also an appearance of strength and solidity which favorably impressed members of the engineering profession. The modern instrument, made by this house, while changed in appearance somewhat to suit the eyes of the present day user, still pre- serves the sturdy, well-made, substantial appearance which did so much to render popular the " Roach Instrument." Although it has a strong appearance, and is in fact as strong as any instrument need to be, it weighs no more than one of the same size made by any other maker. Strength is secured by a system of bracing and ribbing, which enables a saving in much material. lightness is secured by this same system of ribbing and also by the use of aluminum alloy in all places where it is of undoubted benefit. In examining this catalogue the reader's attention is directed to the sturdy appearance of the instruments and to the weight of each. He must remember also that they represent an evolution, the result of a growth of over forty years of experience on the Pacific Coast in all classes of work. /. C. SAL A. ILLUSTRATED CATALOGUE OF MAKING AND REPAIRING OF INSTRUMENTS The first essential for accurate work with any kind of an instru- ment is that it be carefully made of the best materials and that the workmanship be the best obtainable. These desirable results have been reached in my instruments. Only the best materials are used, and the workmen are all first-class men of long experience and special training. The tools used are of the strongest and most modern construction. The instruments for precise work are automatic and of the most approved types. The illustrations give a good idea of the various departments of the establishment, and a visit to the works will well repay those who are sufficiently interested to call. I am always pleased to see my patrons and friends. Attention is called to the cuts of the dividing engine and other tools I use. As remarked in the preface, my instruments are strong and as light as is consistent with proper strength. The dead weight is removed wherever not necessary for stiffness; at the same time, stiffness is secured by properly shaping the parts. Each part is shaped to with- stand the strains it will be called upon to bear, and wherever possible to remove extra metal it has been done, but ribs have been left. A judicious employment of aluminum alloy having a great tensile strength helps to decrease the weight materially, and all bearing parts are of the hardest metals. Joints have been avoided largely by combining as many parts as possible in a single casting. This, while an increased expense in making, is of great value, for it reduces the number of joints and therefore the weak places. ALUMINUM. A great popular demand has of late years arisen for instruments made of aluminum, and in response to the demand, I make instruments with a very large percentage of aluminum when J. C. SALA, SAN FRANCISCO II ordered. These instruments are lighter than the regular make, and the dull silver-like finish is very pleasing. The workmanship on them is of the same high class as on my other instruments, and the customer secures a good instrument subject however to the advantages and dis- advantages mentioned below. The disadvantages of aluminum are its softness, the difficulty of soldering to other metals and its wearing. On the other part there are incontestable advantages for certain parts of instruments where light- ness is especially desired. The aluminum bronze is now considered one of the best materials entering into the manufacture of tubes for telescopes, on account of the great rigidity of this alloy. Alloy of silver and aluminum is certainly a valuable material for graduation, allowing an easier reading than on pure silver. I have been building such parts of aluminum or aluminum alloys on transits, levels and plane tables where the metal and its alloys are of recognized advantage, and have such instruments on hand, but am opposed to an indiscriminate use of this metil in the construction of instruments of precision. In regard to aluminum for surveying instruments, a great many unwarranted statements are made every day and engineers should understand fully this question. Aluminum while a very light metal, is not a non-friction metal by any manner of means. The co-efficient of friction is very high, therefore for all the finer bearing parts a bush- ing of hard metal must be used, otherwise the close fitting of parts so necessary to the instrument of precision is lacking. A transit contain- ing enough aluminum to reduce the weight very considerably, is com- posed of too many parts to be a satisfactory instrument. I use enough aluminum alloy in my instruments to lighten some of the more unim- portant parts, but it is confined to such parts. An instrument must be steady and should have enough weight to secure such steadiness as will enable it to stand wind well. The surface exposed to the wind is considerable, and the wind exercises much force upon it. If the instrument is therefore very light it will tremble in a breeze. Instruments made of extreme lightness must have heavy tripods and it is difficult to see where the advantage of the light top comes in in such case. If an engineer really desires to carry a light 12 ILLUSTRATED CATALOGUE OF instrument it will be better to purchase a small sized transit than a large one so light that it will be an annoyance to use it. I have carefully experimented with the various alloys of alumi- num, and as a result of these experiments believe it is not of such value as to justify its very extensive use in surveying instruments. The best alloys of metals are used, and such as have nearly the same co-efficient of expansion as glass are the preferable, as the optical parts of instruments are of such importance. The co-efficient of glass per linear foot for one degree Fahrenheit is 0.000054 inches; of steel it is 0.000076; brass, 0.000125; aluminum, 0.000148. It may be readily seen that when an instrument is so made that all its parts have the same, or nearly the same, co-efficient of expansion, that it will retain its adjustments under decided changes of temperature much better than one which has various metals with widely differing co-efficients. Alum- inum is the least desirable of metals in use for such purpose. Iron and steel of course would be better than brass were it not for the needle and also the liability to rust in exposed positions. Steel centers for levels are much used now and have their advantages. I put them in when ordered in place of ordinary centers without extra charge. FINISH. The finish of my instruments is of a pleasing brown color, unless ordered otherwise. I finish the instruments in any manner ordered. The natural finish of bronze or any other alloy or metal has a glaring effect upon the eye of the observer, and is therefore objection- able. The black finish is not to be recommended on account of its great affinity for absorbing heat and consequently expanding the more exposed parts of the instrument very rapidly to the detriment of the adjustments. To obviate these inconveniences I have adopted two styles of finish which have given the best possible results. My bright finish, somewhat the color of antique bronze, is not glaring and stands well any wear. My cloth finish on such parts of the instruments as are apt to absorb the heat more rapidly on account of their exposure, is of a pleasant greenish color, and feels to the touch as a soft piece of cloth. It secures a very gradual and uniform expan- sion and contraction in sudden changes of temperature. The dura- bility of this finish is not equal to the bright finish, but lasts about as j. c. SALA, SAN FRANCISCO 13 long as the black finish would. As it is not necessary to finish or polish an instrument so finely when cloth-finished, the cost is less than for the ordinary bright finish. In neither of my finishes enter any material having effect upon the magnetic needle. My instruments do not separate above the levelling screws but are placed in the case directly and in an upright position. The cases have rubber cushions on the bottom to ease all jarring motion in transpor- tation. It ma}^ be seen that the constant endeavor of this house is to maintain its old reputation for furnishing the engineer with an instru- ment he can rely upon. I desire to make at all times an instrument which will need no special puffing or advertising, but will be its own recommendation. To secure these desirable ends, special attention is paid to secure: i st -Careful workmanship and design. 2d Accuracy of division. 3d High powered achromatic telescopes. 4th Equable adj ustments. 5th Lightness, stiffness and strength. 6th Simplicity in parts. These all conduce to ease in manipulation and certainty in results. Every instrument sent from the factory is carefully adjusted and packed in a manner which should insure safe transportation. My experience in packing instruments for so many years when they were exposed to all sorts of usage in transportation, has developed skill in packing, and very few instruments sent by me arrive at their destina- tion with the adjustments impaired in the slightest degree. REPAIR OF INSTRUMENTS. My facilities for repair work of all kinds are unsurpassed. Having been for years the only house on the Coast in this line, and the freight rates to the East being very high, I have repaired instruments of nearly every known make. I am therefore as familiar with the construction and workmanship of the leading instrument makers of this country as with my own make, 14 ILLUSTRATED CATALOGUE OF and can guarantee satisfaction in repairing. My shop is especially well fitted for such work. The most satisfactory way to obtain first-class work in repairs is to send the instrument to me with instructions to put it in thorough order and adjustment. I will give an estimate of the cost if desired, before doing the work. Of course this is the most expensive way of doing the work but it is the cheapest in the end. If it is not thought best to do this, the instrument can be sent with a clear description of the repairs or other work desired, and I will follow instructions. I will do as good work as can be done, taking into account the make, material, workmanship and general state of the instrument as regards condition and extent of the damage done. The cost will be as low as is consis- tent with good work and will be according to the time consumed and material used. The packing of instruments sent for repairs should be carefully attended to. Place the instrument in its own case and then the case into a packing box with the space between filled with excelsior or straw. This will enable it to be .sent safely and at the same time enables it to be shipped at regular rates. Usually higher rates are charged for sur- veying instruments than for ordinary express packages. I will guarantee as good work as it is possible to put on the job, but reserve the right to decline a job if I believe it impossible to put the instrument into such shape as will warrant the owner spending the money on it. My own instruments should always be sent to me for repairs, as by so doing, considerable expense may be saved. I am in a position to duplicate all parts from stock on hand and can therefore repair instru- ments of my own make quickly and cheaply. J. C. SALA, SAN FRANCISCO THE AUTOMATIC DIVIDING ENGINE. 30-INCH CIRCLE This Engine is Used to Make Graduations on Limbs, Verniers, Etc., and is One of the Best ever Built in this Country or Europe. i6 ILLUSTRATED CATALOGUE OF APPARATUS FOR TESTING MAGNETIC INFLUENCE OF METAL. CENTERING APPARATUS -USED FOR TESTING GRADUATIONS. J. C. SALA, SAN FRANCISCO THE LONGITUDINAL DIVIDING ENGINE. Apparatus for Graduating- the Grooves for Cross and Stadia Wires on the Diaphragm of Telescopes. THE COLLIMATOR APPARATUS. For Adjusting the Line of Collimation of Surveying- Instruments. i8 ILLUSTRATED CATALOGUE OF % 03 2 03 TO p J Ci * S o I" S P rt r- &H 2 g O EN O 5- * ^ ^ T3 0> ^ -2 c fe > S o 73 ^ CW H 1^^ S E o g o 03 OS 'S ^ > ^ 03 O S-i 5 03 S H ^ | : O 7i S =M .S ca s ^ g 03 PH S < * w u rt J. C. SALA, SAN FRANCISCO THE COLLAR TESTER. Used in the Construction of Levels, to Ascertain the Uniformity of Collars on Telescopes. CARE OF INSTRUMENTS. In the care of instruments, common sense should play a great part. The tripod legs should never be permitted to become loose, but the nuts and bolts should fit snugly. Before carrying the instrument, care should be taken that it is screwed firmly to the tripod and in no danger of falling off. It is well also to see that it is tight before using the instrument. Before carrying the instrument, the levelling screws should be screwed to a firm seat and the instrument slightly clamped in order to prevent any movement or wear of the centers. The needle should always be clamped, except of course when in use. It is also thought well to permit the needle to swing freely when the instrument is in its case, as it will swing at once into the meridian in which position it is supposed to retain magnetism best. All unnecessary movement on the pivot should be avoided, and when swinging, the motion should be gently checked by the lifter in order to reduce the play to as small an arc as possible. The needle should always be gently let down on the pivot. A silk handkerchief should never be used to clean the glass or lenses of a transit. 20 II^USTRATKD CATALOGUE OF Buttons, knives, keys, wire hat brims, cheap watch chains, etc., have a great effect on the needle of an instrument. Screws should never be turned more than necessary to obtain a firm seat. The slightest movement more will strain them and impair the accuracy of the instrument and reliability of adjustment. A screw should never be so tight that any great effort will be necessary to start it. When the threads of a screw work hard, they should be cleaned with a stiff bristle brush. A tooth brush is excellent. After cleaning the threads with the brush, oil the screw and work it in to its full length and then out again ; the oil should be wiped off with a clean chamois skin and more oil put on and the screw again worked in and out. This operation should be repeated again and again until the screw is clean and works smooth and free. When this result is accomplished, the screw should be run in and out several times without oil and wiped each time to remove all oil. No oil should be left on exposed portions of levelling or tangent screws, as it will collect dust. A gossamer or silk water-proof bag should be carried in the field for the purpose of covering the instrument in case of rain or dust storms coming up. The only oil to be used on an instrument is the very best quality of watch oil and as little of that as is necessary to cause a smooth motion of the parts lubricated; too much will cause the parts to become sticky and gum up. Sometimes marrow is used for lubricat- ing, but it is objectionable because it is liable to become rigid and bind in cold weather. Vaseline is very good, as it is less rigid than watch oil and somewhat softer and less liable to bind than marrow, but it requires renewal often. As an instrument should be as little disturbed as possible in its adjustments, the best lubricating material is that which requires little attention and contains no grit. Watch oil is the best and is the only thing to use on centers and the finer grade of instruments. Sea air has a tendency to destroy the finish of the surface of an instrument; a good plan to follow when working near the seashore is to cover the entire surface with a thin coating of oil. All exposed surfaces moving in contact, such as the object slide, etc., must be kept free from oil, as it will collect dust and sooner or J. C. SALA, SAN FRANCISCO later cause fretting. When any surface begins to fret, it should be carefully examined and a piece of hard wood rubbed on the spot to smooth oif the roughness. If tin.: does not improve the matter, the surface should be slightly scraped with a sharp knife or touched with a very fine flat file and burnished with a polished piece of steel. A little oil can then be applied and the movement tested. If all fretting has disappeared the oil should be very thoroughly wiped off and the parts replaced in position. If any powder is used to reduce the roughness instead of employ- ing a scraper, care should be taken that it is not emery, as that is the worst possible thing to use. Only powdered pumice or some rouge should be used. The telescope glasses should be left in their places as long as it is possible to use them, as any unscrewing will destroy their seat and the adjustment will be impaired. When the glasses however become greatly soiled and it is hard to get a good sight through them they should be washed with alcohol. Chamois skin and soft flannel are the best things with which to wipe lenses. Too much rubbing of lenses will destroy the fine polish of the faces which it is important to preserve and all unnecessary rubbing is to be avoided. When the graduations become greasy, coat them with a thin cov- ering of watch oil and let it stand for an hour or two; then wipe it gently with a piece of soft cloth or chamois and be careful to take off all the oil. Try and avoid as much as possible, touching the edges of the graduations. If an instrument falls, and the centers become bent, it should be sent at once to the maker for repairs, as every turn after the accident only makes the condition of affairs worse The few hints here given it is hoped will be of service to users of instruments, and familiarity in their use will be found to suggest many other things which the man possessed of common sense will be able to adopt and find of service. An instrument is a finely made and delicate machine, but to one who thoroughly understands it, the limit of its delicacy can be under- stood, and some men can do a great deal more to one in the way of repairs than others. The old maxim of ''every man to his trade" is however a good one to follow; the efforts of the owner should be con- fined to the keeping of his instrument clean and ready for service. LOOK OUT FOR YOUR NEEDLE. On account of the great number of strong electric currents over the country, the magnetism of needles is more apt to be disturbed than in days " gone by." Never take a transit into an electric power house. Keep a respectable distance away from dynamos and other electric machinery when carrying a transit. Do not ride on electric cars when carrying a transit, if possible to avoid it. If compelled to ride on an electric car with a transit, let the needle swing freely, and carry the instrument on your lap. Never under any circumstances allow the transit to rest on the floor of an electric car. If using a transit near strong electric currents or near electrical machinery, allow the needle to swing freely. If your office is in an upper story of a high office building, have a piece cf thick rubber to place the transit box on and always allow the needle to swing freely. Surveyors' and Engineers' Instruments l-'OK Field Work PART A Ippp^- jpBBlt THE TRANSIT. J. C. SALA, SAN FRANCISCO THE TRANSIT The most important instrument used in engineering work is the transit, and its invention marked a great advance in the doing of accurate work. It can, with its various modifications, do the work of the compass, the level, and, with more or less accuracy, the work of the chain in measuring distances. It is in fact, a universal instrument and an /Ymerican invention. Its essential parts will be briefly explained. GRADUATIONS. The object for which the transit was invented was to obtain closer results in the reading of angles than was possible with the compass. The graduations therefore, by which close reading is obtained, must be very carefully and accurately cut. Those cut on automatic dividing machines are the only ones to be depended upon, as every line is uniform. The lines must be clear and perfectly straight; to obtain this, only silver should be used, as it is of uniform density, and there is no danger of blowholes or defects in the casting such as are encountered in brass or other materials sometimes used for the purpose and silver-plated afterwards. All graduations on transits made by this house are on solid silver. The graduations on the horizontal plate read in opposite directions from o to 360 degrees and are inclined in the direction of the reading. I especially invite a comparison of the graduations on the limbs and verniers made by my automatic dividing engine mentioned under another heading, and the graduations as now existing on a good many instruments of other makes, and am satisfied that the practiced eye of the connoisseur will at once observe that notwithstanding the extreme fineness of the lines, this advantage is obtained without impairing their distinctness. VERNIERS. A vernier is a device whereby finer readings may be obtained than by any other method. It is in fact an auxiliary scale and is so made that a certain number of divisions on it will equal one more or less on the plate, or limb. If for instance a plate is graduated 26 ILLUSTRATED CATALOGUE OF into degrees and quarters, no angle can be read which is less than fifteen minutes. It can be estimated a little closer, but such a pro- ceeding is only refined guesswork. To obtain a reading say to half minutes, a vernier must be used; this is a scale so divided that thirty divisions on it will equal twenty -nine on the plate. Now by placing the vernier in contact with the plate so that the lines on each end are coincident with two lines on the plate, it may be seen that the line next to the end is not exactly coincident with any line. The next line has an increased space between it and the line nearly opposite on the plate, and that this difference grows uniformly greater until it gets to the middle of the scale when the middle line is exactly half way between two lines on the scale; then the lines begin again to approach until the end line at the other end is coincident with a line on the plate. A little reflection will show that each graduation on the vernier is one-thirtieth smaller than one of the graduations on the plate. As the graduations on the plate are fifteen minutes each, the vernier must be able to show a difference equal to one-thirtieth of fifteen minutes, or thirty seconds. Therefore, to find how closely any vernier will read, it is only necessary to divide the value of a division on the plate by the number of divisions on the vernier. It makes no difference whether the graduations on plate and vernier are straight or on circles, the rule holds good; the vernier may be so graduated to enable a finer reading of the foot or of degrees or any other unit. To read a vernier on a transit, read the degrees on the plate and in the direction indicated by the numbering. The zero of the vernier will indicate the number of degrees, and if it coincides with one of the lines, it gives the exact reading; if it does not coincide with any line, then when the zero point is reached the reading must be on the vernier until a line is reached which coincides with a line on the plate. The number of spaces the line on the vernier is from the zero, indicates the number of units of the ' ' smallest reading " to be added to the reading on the plate as indicated by the zero mark. The graduations on the horizontal plate of the transit are in a circle, and the vernier is on a small plate attached to a circular ring outside the graduated plate. To obtain close readings, the line divid- ing the two plates should be very fine and hardly distinguishable; it J. C. SAI,A, SAN FRANCISCO 27 can only be so if the two plates are in precisely the same plane. If there is a wide space between the graduated plates or one is a trifle higher than the other, the transit is not capable of doing as accurate work as is necessary. The verniers on my transits are placed directly in front where they can be most easily read. THE CENTERS. The centers of a surveying instrument are the fundamental part of such instrument. Upon the axis and bearings depends in the first place the accuracy of measuring either horizon- tal or vertical angles, and also on their trueness depends the closeness of the line between the horizontal or vertical limb and its vernier. Since my predecessor started in business, the instruments built by this firm have been renowned for the trueness and unsurpassed wearing qualities of the centers of their instruments. The fineness of the line between the vernier and the plate depends to a great extent upon the perfect fitting of the centers. No matter how well graduated the plates or how excellent the workmanship in other parts of the instrument, if the centers are not truly fitted, no good work can be done. The centers support all the vital parts of the transit, and for steadiness should be long and fit perfectly at all points so as to insure firm and steady bearings; they must be well turned in order to move freely without binding and to require as little lubricating material as possible. There must be just enough lubricating material on the centers to enable the surfaces to move on each other without grinding; the least additional amount prevents a perfect fit. Any bending of the centers introduces errors and sets up a grinding motion which soon renders the instrument useless. The centers on all my instruments are long and made of the very hardest bell metal. The center of gravity is brought down as low as possible and steadiness thus insured. THE PLATE LKVELS. To obtain correct readings of horizontal angles, the instrument must be level; to make it so, there are two level tubes on the plate at right angles to each other. One is parallel to the line of sight. The one parallel to the line of sight is sometimes placed on the standards supporting the telescope and the other on the plate. It was formerly stated that it did not matter much if the level on the side was a little out of adjustment, as the angles were read from 28 ILLUSTRATED CATALOGUE OF an imaginary vertical line through the center of the telescope tube; it was thought that if the level at right angles was perfectly level, angles could be correctly read even if the other level was out slightly. This idea is no longer entertained, for it may be easily perceived that if the plate is not truly horizontal, all the angles will be too small. The repeated clamping, unclamping and turning of the instrument while making observations, has a tendency to throw the plate slightly out of level, and it is therefore necessary that the plate levels should be extremely sensitive in order that the least amount of deviation may be ascertained and corrected before much harm is done. All levels for close work are ground to a true arc of a circle and must be uniformly ground or they are of no use. A very good idea can be formed of the quality of work put in an instrument by noticing the sensitiveness of the levels; unless all fittings are good, the levels will always be unsteady and a source of annoyance. A maker puts on his instruments as sensitive levels, as he thinks will be good for them to have, and if the bubble is sluggish, it is a pretty sure indication that the workmanship generally is not first-class. If the metal in the centers is soft, a sensitive level will soon tell when any wearing begins. To insure good work and peace of mind it is well to have sensitive levels on an instrument and the value of the graduations known; if the level gets out a little on the work, the operator will know just how much his work is likely to be affected and can govern himself accord- ingly. THE LEVELING SCREWS. These parts of an instrument are more used than any other, and therefore require to be made of hard metal, and the threads must be even and deep; the heads should be broad, in order that a firm hold may be obtained and the screws turned easily. The leveling arrangements of my instruments are fully in accord with the best modern ideas. The parts are strong and the motion easy and uniform. A caution to be remembered in using an instrument is, that when a screw has been brought to a firm bearing^ all turning should stop. An extra effort, however slight, will have a tendency to jam the screw and interfere with easy motion, or bend a thread, and thus open the way for future trouble and expense. J. C. SALA, SAN FRANCISCO 2Q The instruments ordinarily used have four leveling screws arranged in opposing pairs. To level the plate, one pair at a time is turned, each screw in an opposite direction. When the thumbs move towards each other, the bubble goes towards the right; when they move from each other, the bubble goes to the left. Before the opera- tion is commenced, the levels must be parallel with the pairs of screws. Four screws are most convenient for ordinary instruments, but transits graduated to read angles of io /x or less, generally have only three leveling screws. The objections to three screws are that they make necessary a little increase in the size of the tripod head, and con- sequently larger tripod legs and a larger carrying case. The advan- tages of three leveling screws are that the instrument is made steadier, the centers are relieved of some strain and a perfect horizontal adjust- ment is obtained, thus insuring a high degree of accuracy. Instruments can be supplied with three or four screws as desired. All my leveling screws are capped and so constructed as to prevent dust getting on the threads. The transits are also supplied with shift- ing centers, which permit of a small lateral movement of the upper part of the transit after the tripod is set, and thus enables an accurate setting over a point. TRIPOD ATTACHMENT. Several devices are in use for securing the instrument to the tripod, but none are so satisfactory as the screw. By the screw the fastening is secure, and timely warning is given before the hold loosens to an extent which will cause a severance of the parts. The only real objection urged against the screw, is the time it takes to attach the instrument by means of it; this objection I have overcome by providing the bottom plate with a double-threaded screw. One single turn and a half will fasten the instrument firmly in place. THE TELESCOPE. We now come to a part of the transit which is of not much less importance than the graduations. The telescope should have a large field and give a clear definition; it should be achromatic. It is not necessary here to give any description of the principle of the telescope, as all good works on optics sufficiently deal with the subject. It is sufficient to state that my telescopes combine all the latest improvements. The question of power has been carefully considered, and with forty-two years' experience to guide me, the 30 ILLUSTRATED CATALOGUE OF telescopes placed on my transits are equal to all demands which will ever be made upon them. The glasses are ground to special formula, and the best quality of glass used. The telescope tubes are castings, and carefully finished; this insures rigidity and prevents a warping of the telescope. This is the invention of the present head of this house, and was never used by any maker before my instruments were thus fitted. The advantages over drawn brass tubes are apparent. The axis of the telescope is large, and of hard solid bell metal ; the ends are corrugated where they rest in the uprights, thus giving a large bearing with steadiness of motion and securing the line of colli- mation. The telescope is so placed on the axis that it is perfectly balanced when the sun shade is on. The object end is furnished with a slide protector which prevents dust and grit from injuring the slide, upon which the perfection of the collimation depends. The eye piece is provided with an improved screw adjustment, permitting the cross hairs to be accurately brought into focus without shaking or jarring the instrument. The telescope swings freely and in a full circle. The eye piece is erecting but can be made inverting if so ordered. An erect eye piece intercepts more light than an inverting one, but is convenient to use. With a little practice, an inverting eye piece offers no great inconvenience, and for stadia work, where brilliancy of the object observed is desirable, it is to be recommended. STANDARDS. The standards, or uprights, are of the form best calculated to do the work required, of supporting the telescope and its various attachments. An expanded base is well secured to the upper plate and an adjustment is provided for securing the revolution of the telescope in a vertical plane. COMPASS. As the graduations only occupy a narrow ring on the edge of the plate, there is a vacant space inside the ring and between the standards which is utilized by placing a compass box therein. The needle is as long in all cases as it is possible to put in. The utility of the compass as a portion of the transit is too apparent to require any special remarks. The compasses on my transits are as carefully made as any other part of the instrument, and especial care is taken that the J. C. SAIvA, SAN FRANCISCO 31 graduations will coincide exactly with the graduations on the horizontal limb; this, if not done, sometimes causes wide differences in bearings of lines when observed with different instruments. The line of colli- mation of the telescope must exactly coincide with the north and south line engraved on the compass ring, and the line through the o and 1 80 graduations on the horizontal limb. As to what is embodied in a good compass, see chapter on compasses. CLAMP AND TANGENT SCREWS. The clamp and tangent screws are of German silver or aluminum alloys, either metal being used where it is deemed best. For clamping the whole instrument, the tangent screws are either of the improved spring pattern or have two opposing screws of the old pattern. While this latter form requires the use 01 both hands in setting the sight, it has the advantage of being firmly set and requiring no further attention. With an opposing spring, the screw works as it were, against a cushion, and is liable to derangement if the instrument is standing for any length of time over one point as frequently happens. The upper tangent screw controlling the move- ment of the plates, is of the improved spring pattern, as it is placed where it is under easy control and is convenient to use, requiring only one hand. The heads of all screws are broad and easy to grasp and turn. TRIPOD. The tripod legs are made round, but split leg tripods are furnished when ordered; the upper ends of the legs are pressed firmly on each side of a strong tenon on the solid bronze head by a bolt and thumb screw on opposite sides of the leg. To set the tripod up easily, the legs should move freely but not loosely on this tenon; when they become loose they may be tightened by means of the thumb screw- this obviates the necessity for carrying a screw driver or wrench for the purpose. A strap with buckle is fastened to one of the legs near the lower end for the purpose of fastening the legs together for shipment. The lower end of the leg has a brass shoe with iron point, securely fastened and riveted to the wood. Extension tripods can be furnished if desired; they are conven- ient when using the transit in confined spaces, as on very steep hillsides. 32 ILLUSTRATED CATALOGUE OF ATTACHMENTS OF THE TRANSIT. The foregoing description is of what is known as the plain transit with it, lines can be ranged and angles turned to right or left of th< lines. To increase its range of usefulness, there are certain attach ments which are termed "extras." The first generally added, is 5 level tube beneath the telescope and a clamp and tangent screw on th< standards to control it; by adding this level tube, the transit can thei be used for leveling. A vertical circle, or arc, added to the telescop< axis with a vernier on the standard, makes it possible to take vertica angles. Two extra hairs (called stadia hairs) placed inside the telescop< enable distances to be measured by rod readings. A graduated heac placed on the tangent screw of the telescope makes what is termed i gradienter; by its means, grades can be established, and horizonta distances^ vertical angles and differences of level can be measured witl great rapidity. THE GRADIENTER. The head of the screw on the clamp for the telescope is divided into one hundred equal parts; over it is a scale which is divided into spaces, each of which is equal to one revolutior of the screw, so that by comparing the edge of the head with the scale the number of revolutions made can be ascertained. If the telescope i* clamped and the screw turned, it will be seen that the end of th telescope will be moved vertically, and as one complete revolution o: the screw will move the horizontal cross wire over a space of one fool on the rod held at a distance of one hundred feet, it may be easily seer that distances can be read by means of the gradienter with the same facility as with the stadia. Grades can be established as follows: First level the instrumenl and then bring the bubble under the telescope to the center of the tube, move the gradienter screw until the zero is opposite the zero on the scale, and clamp the telescope; then turn off as many spaces on the head as there are hundredths of feet to the hundred in the grade to be J. C. SALA, SAN FRANCISCO 33 established. Sometimes there are fewer graduations on the screw than stated above, but the principle and method are the same. For setting off the variation of the needle, an adjustable arc is often placed inside the compass box. In my transits, the variation arc is placed outside the compass ring, thus obtaining a large radius, and being graduated to minutes, the engineer is enabled to read and set the variation with ease. SAEGMULLER SOLAR ATTACHMENT. As the transit is sometimes used to retrace lines which have been previously run with a needle, or to run lines the bearing of which it is necessary to correct by observations on the sun in order to obtain the true bearing, there have been various forms of solar attachments invented. The best known and most widely used are the Burt and the Saegmuller; I keep both makes and put them on any transit to order. Directions for their use are given in all standard works on survey- ing, and the makers get out special direc- tions for use, with tables, etc. The Saegmuller has the advantage over the Burt of having a telescope, and a transit fitted with it can be used for sighting down shafts like a mining SAEGMULLER SOLAR ATTACHMENT. transit. The transit can be provided with open sights attached to the standards to make offsets at right angles to the line of collimation of the telescope, if such sights are desired. A transit with all the attachments mentioned, is called a complete transit. All transits are furnished with a carrying case supplied with a leather strap, rubber supports, good lock and hooks, and contains plumb bob, sun shade, adjusting pins and magnifying glass. 34 ILLUSTRATED CATALOGUE OF TRANSIT No. 1-PRICE $185. J. C. SALA, SAN FRANCISCO 35 TRANSIT No. I. The engineers' plain transit as manufactured by J. C. Sala, has .11 1 1 -inch telescope, which is provided with achromatic lenses of high ower, slide protector, sun and dust shades. The telescope reverses at >oth ends. The object glass of the telescope has an aperture of i^ tiches; its eye piece is provided with a screw adjustment. The axis >f the telescope is large and of .solid hard bell metal. The horizontal date is of seven inches diameter, with double verniers graduated on olid silver, reading to thirty seconds. The circle of the compass box 5 graduated to thirty minutes, the needle is 43/6 inches long, with agate earing; the compass box has on its outside, a variation plate with ernier reading to single minutes. The small graduated bubbles of the levels on the horizontal plate re ground and graduated to the greatest accuracy; the tangent screw f the horizontal plate is provided with a compensating spring; the angent screw to the center of the instrument is also provided with a ompensating spring. The leveling screws are protected with a dust nd grit cap covering the whole of the thread of these screws; they est upon a shifting plate which moves upon the bottom plate screwed o the tripod; this allows the instrument to be shifted accurately over .ny given point, and when the leveling screws are set, the shifting late becomes fixed. The center upon which most of the efficacy and .ccuracy of the instrument depends, has a bearing length of 4^ inches. The tripod is made with either split, solid or extension legs, as lesired. The case is furnished with a leather strap, rubber supports, ^ood lock and hooks, and contains plumb bob, sun shade, adjusting >ins and magnifying glass. ILLUSTRATED CATALOGUE OF ENGINEERS' TRANSIT, No. 2-PRICE $210. The description of this instrument is the same in size and partic- ulars as No. i , with the addition of clamp and tangent attachment tc axis, and level to telescope, with a finely ground and graduated bubble J. C. SALA, SAN FRANCISCO 37 ENGINEERS' COMPLETE TRANSIT, No. 3 PRICE $235. This instrument is the same in size and particulars as No. i , with le addition of clamp and tangent attachment to axis and level to ilescope, with a finely ground and granulated bubble; vertical arc with ernier reading to thirty seconds; (all graduations on solid silver) this istrument is the most desirable, having all the necessary attachments for sneral work, being of good size, strong and yet not too heavy to carry. ILLUSTRATED CATALOGUE OF SURVEYORS' TRANSIT, No. 4-PRICE $250- Has a horizontal plate 8 inches in diameter, with two verniers reading to thirty seconds. Length of needle 5 inches. Clamp and tangent attachment to axis and level to telescope, with a finely ground and graduated bubble; vertical circle, 5 inches in diameter, and vernier reading thirty seconds. For other particulars, see description of No. i. J. C. SALA, SAN FRANCISCO COMBINED MINING, MOUNTAIN AND SOLAR TRANSIT. I manufacture a combined mining and mountain transit with two telescopes parallel to each other; the upper one, although detachable, is securely fastened to the one revolving in the standards, by supports and thumb screws. The telescopes are supplied with achromatic lenses of twenty magnifying power, rack movement for the object glass, fixed or adj ustable stadia hairs, movable prism to fit the eye pieces of either telescope. To the telescope revolving in the standards is attached an hour arc and center column for a solar attachment, and under it a level of precision ; the divisions of its bubble reading to ten seconds of arc. Both telescopes are provided with a slide protector and a sun shade, also with a silver reflector for illuminating cross hairs in mining or night work. The vertical circle attached to the axis of the telescope and its vernier are graduated on solid silver, and read to either thirty seconds or one minute, as desired. The micrometer tangent screw with compensating spring on the upright, is provided with a gradienter attachment. The standards are also furnished with open sights giving a line of 90 to the line of colli- mation of the telescopes. The circle of the compass box is graduated to thirty minutes, the needle being 3^ inches long, with agate bearing. The compass box has on its outside, a variation plate with vernier reading to minutes. The small graduated bubbles of the levels on the horizontal plate are ground and graduated to the greatest accuracy. The horizontal limb and verniers are graduated on solid silver, and read directly under the eye piece and object glass of the telescope to thirty seconds on a beveled surface at an angle of 30. The tangent screw is provided with a compensating spring. The leveling screws are protected by caps and rest upon a shifting plate which moves upon the bottom plate screwed to the tripod; this allows the instrument to be shifted accurately over any given point, and when the leveling screws are set, the shifting plate becomes fixed. The center, upon which most of the efficiency of the instrument depends, has a bearing length of four inches. The tripod is made with either split, solid or extension legs, as desired. H.l.rSTRATKl) CATAIX)GUE COMBINED MINING, MOUNTAIN AND SOLAR TRANSIT, No. 5, WITH DOUBLE TELESCOPE TO TAKE VERTICAL ANGLES PRICE $335. J. C. SALA, SAN FRANCISCO COMBINED MINING, MOUNTAIN AND SOLAR TRANSIT, No. 5 SHOWING SOLAR ATTACHMENT, ILLUSTRATED CATALOGUE OF LIGHT MOUNTAIN TRANSIT, No. 6-PRICE $220. Having a horizontal plate 6 inches in diameter, with double v< niers reading thirty seconds; improved spring tangent screws, magne needle 3^ inches long, with adjustable variation arc, 4-inch vcrtii circle. A telescope 8 inches in length, with high magnifying pow< aperture of object glass i inch; erect eye-piece, and reversing at bo ends. To the tangent screw of the vertical arc is attached a gradie ter, and by its means, grades, horizontal distances, vertical angles a: differences of level can be obtained. J. C. SAI.A, SAN FRANCISCO 43 COMBINED MINING AND SOLAR TRANSIT, No. 7 PRICE, $290. This instrument is the same as No. 4, only differing from it in having the Saegmuller attachment; this answers all the purposes of a side telescope in taking perpendicular sights in mining work. The Saegmuller Solar Attachment to this instrument enables the engineer to establish accurately the astronomical meridian The advantages of this solar attachment are: It is more accurate, it is simpler and easier of adjustment, it can be used when the sun is partly ocscured by the clouds, it can be used where the sun is quite close to the meridian, the time can be obtained with it reliable to within a few seconds with perfect ease, and as stated above, it can be used as a vertical telescope in mining surveying. ILLUSTRATED CATALOGUE OF HOW TO ADJUST THE TRANSIT. Every transit should be properly adjusted by the maker befor leaving his hands, they are however liable to derangement by transpor tation, and a few remarks on the adjustments will not prove useless These are the levels, the standards, the line of collimation, the vertica circle and the level to telescope. To ADJUST THE LEVELS. Set the instrument upon its tripoi as nearly level as possible, unclamp the plates and bring the levels ii line with the leveling screws, and by these bring the bubbles betweei the lines, and when both are in place, turn the instrument half-wa; around; if the bubbles stay in the center, they will need no correction but if not, turn the small screw at the ends of the levels with tb adjusting pin until the bubbles are moved half the error, then bring tli bubbles in center by the leveling screws, and repeat the operation unti the bubbles remain in the center, and the adjustment will be complete Care should be taken to loosen one end of the level screw befor tightening the other, so as to not strain the tube. To ADJUST THE STANDARDS. Set up the instrument in a plao where a very steep point can be obtained, giving a long vertical line Carefully level the instrument and bring the wires on some high object clamp the plates, then bring the telescope down until the wires striki some well defined point at the base, turn the instrument half round, fh the wires on the same high point, clamp the plates and bring th< telescope down; if the wires strike the same point as before, the vertica adjustment is correct, if not, by means of the adjusting screw, place( in one of the standards, raise or lower the adjusted piece half th< difference found, and repeat until the adjustment is correct. To ADJUST THE LINE OF COLLIMATION. Set the instrumen firmly on the ground and level it carefully, and then having brough the wires into the focus of the eye piece, adjust the object glass 01 some well defined point, as the edge ot a chimney or other object, at i distance of from 200 to 500 feet; determine if the vertical wire i: plumb, by clamping the instrument firmly and applying the wire to th( J. C. SALA, SAN FRANCISCO 45 ertical edge of a building, or observing if it will move parallel to a point taken a little to one side; should any deviation be manifested, loosen the cross-wire screws, and by Hie pressure of the hand on the head outside the tube, move the ring around until the error is corrected. The wires being thus made respectively horizontal and vertical, fix their point of intersection on the object selected; clamp the instrument to the spindle, and having revolved the telescope, find or place some rood object in the opposite direction, and at about the same distance from the instrument as the first object assumed. Great care should always be taken in turning the telescope, that the position of the instrument upon the spindle is not in the slightest degree disturbed. Now, having found or placed an object which the vertical wire bisects, unclamp the instrument, turn it half way around and direct the telescope to the first object selected; having bisected this with the wires, again clamp the instrument, revolve the telescope, and note if the vertical wire bisects the second object observed. Should this happen, it will indicate that the wires are in adjustment, and the points bisected are with that of the center of the instrument, in the same straight line; if not, then move one-quarter of the difference, using the two capstan head screws on the sides of the telescope, these being the ones which affect the position of the vertical wire, and repeat until the line of collimation is adjusted. Remember that the eye piece inverts the position of the wires, and therefore that in loosening one of the screws and tightening the other on the opposite side, the operator must proceed as if to increase the error observed. To ADJUST THE VERTICAL CIRCLE. Having the instrument firmly set up and carefully leveled, bring into line the zeros of the circle and vernier, and with the telescope find or place some well defined point or line, from 100 to 500 feet distant, which is cut by the horizontal wire. Turn the instrument half way around, revolve the telescope, and fixing the wire upon the same point as before, note if the zeros are again in line; if not, loosen the capstan head screws, which fasten the vernier, and move the zero of the vernier over half the error; bring the zeros again into coincidence, and proceed precisely 46 ILLUSTRATED CATALOGUE OF as at first, until the error is entirely corrected, when the adjustment will be complete. A slight error may be most readily removed by putting the zeros in line and then moving the wire itself over half the interval. The level is adjusted by bringing the bubble carefully into the center by the nuts at each end, and when there is a vertical circle on the instrument, this should be done when the zeros of the circle and vernier are in line and in adjustment. To ADJUST THE lyEVEL ON TELESCOPE. First level the instru- ment carefully, and with the clamp and tangent movement to the axis, make the telescope horizontal, as near as may be, with the eye; then, having the line of collimation previously adjusted, drive a stake at a convenient distance, say from 100 to 300 feet, and note the height cut by the horizontal wire upon a staff set on the top of the stake. Fix another stake in the opposite direction, and at the same distance from the instrument, and without disturbing the telescope, turn the instru- ment upon its spindle, set the staff upon the stake and drive in the ground until the same height is indicated as in the first observation; the top of the two stakes will then be in the same horizontal line, however much the telescope may be out of level. Now remove the instrument from fifty to one hundred feet to one side of either stakes, and in line with both; again level the instrument, clamp the telescope as nearly horizontal as may be, and note the heights indicated upon the staff placed first upon the nearest and then upon the most distant stake. If both agree, the telescope is level; if they do not agree, then with the tangent screw move the wire over nearly the whole error, as shown at the distant stake, and repeat the observation as described. Proceed thus until the horizontal wire will indicate the same height at both stakes, when the telescope will be truly horizontal. Taking care not to disturb its position, bring the bubble into the center by the little leveling nuts at the end of the tube, when the' adjustment will be completed. J. C. SAI,A, SAN FRANCISCO 47 THE LEVEL. The level is an instrument of precision for ascertaining the differ- ence in elevation between points. There are two different forms in general use. The Dumpy level is of simple construction and excellent for working; it retains its adjustments much longer than a Y level, but once out, the adjustments are not so easily made as in the latter, and for this reason many prefer the Y level. Both forms are made by this house. The remarks about the telescope, centers, leveling .screws, clamp and tangent screws, level tubes, tripods, and general workmanship in the chapter 011 the transit, apply also to our levels. The workmanship is the best and the latest improvements are adopted. 48 ILLUSTRATED CATALOGUE OF ENGINEERS' Y LEVEL, No. 8 PRICE $150. The telescope is 21 inches long, has a power of 50 diameters, aperture of object glass i^ inches, clear; erect eye piece, achromatic perfect, defines sharply, has a flat field with great penetrating power, which is essential in good leveling. The eye piece is provided with a semi-circular movement, very convenient for focussing the cross wires without shaking the instrument. The telescope has two extra wires for stadia measurements. The collars are of the hardest metal, with clamp .screws to keep the cross wires in horizontal position. The spirit level is 8^ inches long; the bubble is very sensitive and finely grad- uated. The object end is provided with a slide protector, which pre- vents dirt or dust from injuring the slide upon which perfect adjustment depends. The center is 3^ inches long, stout and of the hardest bell metal or steel. The four large leveling screws are perfectly covered. It has an improved spring tangent screw and a clamp to the center. The bar is 13 inches long, very heavy, and it is attached to the tripod in the same manner as transit No. i. The case is furnished with heavy leather straps, rubber supports, good lock, adjusting pins and sun shade. ENGINEERS' Y LEVEL, No. 9 PRICE $140. Telescope 19 inches, (description same as No. 8) bar n inches long, heavy; length of spirit level 7^ inches. Center and leveling screws (as described in No. 8). ENGINEERS' Y LEVEL, No. 10 PRICE $130. Telescope 17 inches long, aperture of object glass i^ inch, (for description see No. 8) bar 10 inches long, spirit level 6]/ 2 inches, with a fine graduated bubble. Center and leveling screws (as described in No. 8). This instrument is the most convenient size for general work. J. C. SALA, SAN FRANCISCO 49 DUMPY LEVEL, No. 11 PRICE $90. This level is expressly designed for irrigation, having an erecting telescope 16 inches long, with a magnifying power of thirty diameters, and a large sensitive bubble, with the level tube enclosed in a revolving protecting tube, thus allowing the bubble to be perfectly covered when not in use. This level has been approved by competent irrigation engineers, as being the most suitable for their use. No. 12 Architects' or builders' level, with a telescope 12 inches long, erect eye piece, ground graduated bubbles. Price $60. No. 13 Farmers' or drainage levels of all description, from $15 to $40. 50 ILLUSTRATED CATALOGUE OF HYDROGRAPHIC Y LEVEL. On special order I make a superior Y level with three leveling screws in place of four, and a reflecting mirror to enable a quick and accurate setting of the bubble without rendering necessary a change of position by the observer. Price upon application. REVERSION LEVELS. Sometimes the wyes in which the level telescope rest or the collars of the telescope wear unequally, and the bubble underneath the teles- cope if desired can be so ground that the telescope can be revolved in its collars and the bubble thus brought on the upper side, and indicate in that position also a level line (thus correct levels can be taken when the collars are badly worn). While this is an ingenious idea, it is based upon the same principle as the repeating of angles in transit work. If the engineer desires to go to all the trouble necessary, he can do as good work with his instrument supplied with an ordinary bubble. I grind bubbles for reversion levels to order. HOW TO ADJUST THE LEVEL. To ADJUST THE LEVEL BUBBLE. Clamp the instrument over either pair of leveling screws and bring the bubble into the center of the tube; now turn the telescope in the wyes, so as to bring the level tube on either side of the center of the bar. Should the bubble run to the end, it would show that the vertical plane, passing through the center of the bubble, was not parallel to that drawn through the axis J. C. SALA, SAN FRANCISCO 51 of the telescope rings. To correct the error, bring the bubble entirely back, with the capstan head screws, which are set in either side of the level holder, placed usually at the object end of the tube. Again bring the level tube over the center of the bar, and the bubble to the center; turn the level to either side, and if necessary, repeat the correction until the bubble will keep its position, when the tube is turned half an inch or more to either side of the center of the bar. The necessity of this operation arises from the fact that when the telescope is reversed end for end in the wyes, in the other and principal adjustment of the bubble, we are not certain of placing the level tube in the same vertical plane, and therefore it would be almost impossible to effect the adjust- ment without a lateral correction. Having now, in a great measure, removed the preparatory diffi- culties, we proceed to make the level tube parallel with the bearings of the Y rings. To do this, bring the bubble into the center with the leveling screws, and then, without jarring the instrument, take the telescope out of the wyes and reverse it end for end. Should the bubble run to either end, lower that end, or what is equivalent, raise the other by turning the small adjusting nuts on one end of the level, until by estimation half the correction is made; again bring the bubble into the center and repeat the whole operation, until the reversion can be made without causing any change in the bubble. It would be well to test the lateral adjustment, and make such correction as may be necessary in that, before the horizontal adjustment is entirely completed. To ADJUST THE WYES. Having effected the previous adjust- ments, it remains now to describe that of the wyes, or, more precisely, that which brings the level into position at right angles to the vertical axis, so that the bubble will remain in the center during an entire revolution of the instrument. To do this, bring the level tube directly over the center of the bar and clamp the telescope firmly in the wyes, placing it as before, over two of the leveling screws, unclamp the socket, level the bubble, and turn the instrument half way round, so that the level bar may occupy the same position with respect to the leveling screws beneath. Should the bubble run to either end, bring it halfway back by the Y nuts on either end of the bar; now move the telescope over the other set of leveling screws, bring the bubble again 52 ILLUSTRATKD CATALOGUE OF into the center and proceed precisely as previously described, changing to each pair of screws, successively, until the adjustment is very nearly perfected, when it may be completed over a single pair. The object of this approximate adjustment, is to bring the upper parallel plate of the tripod head into a position as nearly horizontal as possible, in order that no essential error may arise, in case the level, when reversed, is not brought to its former situation. When the level has been thus completely adjusted , if the instrument is properly made and the sockets well fitted to each other, and the tripod head, the bubble will reverse over each pair of screws in any position. To ADJUST THE LINE OF COLLIMATION. Set the tripod firmly, remove the Y pins from the clips, so as to allow the telescope to turn freely; clamp the instrument to the tripod head, and by the leveling and tangent screws bring either of the wires upon a clearly marked edge of some object, distant from 100 to 500 feet; then with the hand, carefully turn the telescope half way around, so that the same wire is compared with the object assumed. Should it be found above or below, bring it half way back by moving the capstan head screws at right angles to it, remembering always the inverting property of the eye piece; now bring the wire again upon the object, and repeat the first operation until it will reverse correctly. Proceed in the same manner with the other wire until the adjustment is completed. Should both wires be much out, it will be well to bring them nearly correct before either is entirely adjusted; when this is effected, bring the wires in the center of the field of view by the other capstan screws. The inverting property of the eye piece does not effect this operation, and the screws are moved direct. To test the correctness of the centering, revolve the telescope, and observe whether it appears to shift the position of an object. Should any movement be perceived, the centering is not perfectly effected. It may be here repeated, that in all telescopes, the position and adjustment of the line of collimation depends upon that of the object glass; and, therefore, that the movement of the eye piece does not affect the adjustment of the wires in any respect. J. C. SALA, SAN FRANCISCO THE SURVEYORS' COMPASS. 53 One of the oldest of instruments for ranging lines, the compass has at last come to be regarded as of little value in accurate work. In running old lines however, and for work of a preliminary nature, it is safe to say the compass will never be supplanted. There are certain classes of work, requiring speed rather than accuracy, which are very satisfactorily performed by means of the compass, and to supply the demand, I keep a good stock of all kinds. THK XKKDI.K. All compass work depends upon the accuracy with which the needle reads. It is essential therefore that the needle l>e of hard steel and tempered throughout to retain its magnetism. It should be thin and at the same time have enough surface to be strongly magnetic. The needle should be perfectly straight and the two points should read precisely 180 different in any part of the box. It should be so sensitive that when drawn away from its pointing by a piece of metal, it will always return to the same reading when the attraction is with- drawn. Four things affect the sensitiveness of a needle; the form of the pivot on which it swings, the sharpness of the pivot, the strength of the magnetism, and the bearing on the jeweled pivot. When a needle is sluggish it should be lifted off the pivot and the point of the pivot examined with a glass; if it is dull or bent, take a fine oil stone, and holding it against the point at an angle of about 25, turn the compass slowly on its center. This will grind a good point if carefully done. If, after ascertaining that the point is sharp, the needle is still not sensitive, it may then need to be remagnetized. If the pivot point is bent or not truly ground, the two ends of the needle will not read 180 different; to preserve it, the needle should always be screwed up when the instrument is carried. As the generally accepted theory is that a needle retains its mag- netism longer when lying in the meridian, it is well to always let the 54 ILLUSTRATED CATALOGUE OF needle swing freely when the instrument is not in use, taking care to keep the instrument level so the needle can not bend the pivot. A quivering motion in the needle when swinging freely, is a very good indication that it is well made, the center of gravity being low. REMAGNETIZING. To remagnetize a needle, take it off the pivot and hold the south end in the left hand; take a good magnet in the other hand and place the positive end on the needle. Draw the magnet slowly toward the north end and clear off the needle. Return it in a large circle back to the starting point and repeat the operation until the work is done. Never rub a magnet back and forward on a needle. ERRORS IN THE INSTRUMENT. To determine whether the com- pass itself has iron, in it, set three stakes in the ground in the form of a triangle. Set on one and read the angle (preferably 10 or 15 degrees) between the other two. Take this angle on different parts of the grad- uated circle, and if the reading is the same at all points there is no local attraction in the instrument. In a compass attached to a transit, it is a good plan after setting the instrument so that both compass needle and vernier read 0, to go round the circle, setting the vernier ten degrees ahead each time, and noting whether the compass needle also describes an arc of precisely ten degrees; if it does not, there is some attraction in the instrument. A fine coil of wire is placed on the south end of needles used in the northern hemisphere to balance them; this wire must be shifted as the compass is changed to another latitude, and in the southern hemis- phere must be placed on the north end of the needle. GRADUATIONS. The graduations on the compass box should begin at the north point, and run 90 in both directions; then decrease to again at the south point. In order that the needle reading may indicate the direction of the telescope, the lines joining the zeros of the ordinary compass ring must be in the same vertical plane with the line of collimation of the telescope, and the letters denoting the cardinal points, east and west, must be transposed; /. $1.00 and $1.25. 6 oo 10 oo 11 50 i 25 74 ILLUSTRATED CATALOGUE OF CHESTERMAN'S STEEL TAPES, No. 41. In leather case, with flush handles. 25 feet $ 4 50 66 feet 3 8 oo 33 " 5 oo 75 50 " 6 oo 100 9 oo 10 oo CHESTERMAN'S METALLIC TAPES, No. 42. 33 feet. 50 " . 66 " . ..$2 25 2 75 .. 3 oo 75 feet. IOO " . $3 75 4 50 J. C. SALA, SAN FRANCISCO 75 PAINE'S PATENT STEEL TAPES, No. 43. In leather case, with flush handles. 33 f eet $5 oo 75 feet. 50 " 6 oo 100 " . 66 " 7 50 .$ 9 oo EDDY'S IMPROVED STANDARD STEEL TAPES, No. 44. Metal lined with flush handles, in leather-covered case, graduated in icths or i2ths of a foot or metric measure. Feet 33 5O Price, each $5-5O 6. 7 5 8.25 9-75 100 12.00 7 6 ILLUSTRATED CATALOGUE OF THE RIVAL STEEL TAPE, No. 45. The Rival is made of the best steel ribbon of sufficient width (^ inches) and thickness to insure strength and durability, yet light enough not to require a cumbersome case. The steel ribbon is etched to such a depth as to let the marks appear as if embossed, thus guar- anteeing their distinctness after years of hard service. The case is made of stout brass, nicely nickel plated and is more durable than any other used ; it is compact in form, and the handle folds nearly flush with the case. I respectfully invite a critical comparison of the Rival steel tape with the cheaper grades extensively advertised and quoted at a similar price. A comparison will show that the Rival rests upon its intrinsic merits as a reliable, low-priced tape. Rival Steel, 50 feet long, in loths or i2ths $4 oo " 75 " " " " 5 50 100 oo STEEL TAPES OF ANY DESIRED LENGTH MADE TO ORDER. J. C. SAI.A, SAN FRANCISCO 77 METALLIC WARP TAPES, No. 46. These tapes are made of the best linen tape with wire threads to prevent stretching, and by our process of making are always soft and pliable. The ends are reinforced with leather to prevent wearing, and all the cases have our new improved flush handle. Graduated in loths, with links on opposite side. Metallic Tape, ^ inch wide. Feet 25 33 40 Price, each $1.30 33 1.50 50 2.00 66 2.30 75 2-75 100 3.10 Invented by Ernest McCullough, Civil Engineer. PATENT TAPE LEVEL, No. 47 PRICE $1.00. This little device, a California production, is meeting with deserved favor wherever used. The above cut is full size ; the weight of the level is only one ounce. It is used by clamping to the tape, about one foot from the handle, by means of the two springs shown, and can be attached and detached instantly. ILLUSTRATED CATALOGUE OF POCKET LEVEL, No. 48. Bubble mounted in lacquered brass tube upon brass base. 3 6 9 12 inch. $ -5 i.oo r -75 2 -5 Extra fine ground spirit-level, mounted in bell-metal tube and rendered adjustable to the base by capstan screws ; very delicate. 6 9 12 inches. $7.50 9.00 10.50 LOCKE'S HAND LEVEL, No. 49. Bronze, in good leather case oo ABNEY'S REFLECTING LEVEL, No. 50 PRICE $13.50. Abney's Reflecting Level or Pocket Altimeter, improved, combin- ing the uses of both "Locke's Hand Level" and "Clinometer," in leather or mahogany box. No. 51. Same as above, but with compass and socket for Jacob staff. Price, $16.00. J. c. SAtA, SAN FRANCISCO 79 SALA'S TELESCOPIC HAND LEVEL, No. 52. The Sala Hand Level is an entirely new instrument, and consists of a telescope magnifying six times. The tube is provided with the level and prism usual in other hand levels. In the tube is fixed a diaphragm with stadia wires adjusted to the ratio of one foot to fifty feet, thus enabling an engineer to quickly measure distances in prelim- inary surveying. The eye piece and object glass are adjustable as in ordinary transit telescopes. Price, with bather case, $15.00. BOXWOOD CLINOMETER RULE, No. 53-PRICE $11.50. Superior 12 inch, attached compass E, two bubbles C and D, folding sights A B, and arc F of 90, for each degree of which the corresponding rates between horizontal distance and rise or fall is found upon the inclination scale G ; in morocco case. So ttUJSTRATUD CATALOGUE OP THE ATTWOOD CLINOMETER. No. 54. This is a very useful and practical instrument for the use of the miner, prospector, millman and foreman of mines. It is light and can be carried in the pocket. With the aid of a small straight-edge, any inclination or angle can be determined. It is admirably adapted for the arranging of sluices and setting of amalgamating plates or timber- ing in drifts or inclines in a mine. SALA'S ALUMINUM CLINOMETER, No. 55. My Aluminum Clinometer is an improvement on the Attwood Clinometer in so far as it is lighter and not liable to warp when alter- nately exposed to damp and very dry atmospheres. Another peculiarity consists in the disposition of the sights, which are inserted in the short narrow upright sides, which disposition affords them greater protection; also the adaptation of the dial and the compass box of the same, on the face of the instrument, is novel. The horizontal and vertical levels are inserted in the top and side faces as they are in the Attwood Clinometer. The size of the instrument is 6x3^ x^ inches, making it small enough to be carried in the pocket. Price, in leather case, $15.00. J. 0. SAtA, SAN FRANCISCO 81 SALA'S ODOMETER, No. 56- PRICE $17.00. For measuring distances by a wagon. It is enclosed in a brass box, 4^ inches diameter, furnished with leather case with double straps to fasten to the center of the wheel. It is the most correct Odometer in practical use. PEDOMETERS, No. 57. Pedometers are pocket instruments for measuring the distance traversed in walking, the number of miles being registered by a mechanism, inclosed in a nickel-plated watch casing, and operated by the motion of the body. Directions accompany each instrument. Watch size, registering 20 miles and divided in % of mile $ 5 oo The same, with three faces and hands, registering single steps... 9 oo Passometer, watch pattern, nickel case, with three hands, regis- tering 25,000 steps I0 ILLUSTRATED CATALOGUE OF PLUMB BOBS, No. 58. Plumb Bobs of the most improved shape with steel point, frc ii.oo to $5.00, according to size and weight. J. C. SALA, SAN FRANCISCO C. SALA'S ILLUMINATED PLUMB BOB, No. 59 Price $10 and $12. 9 Patented October 3oth, 1883. This simple instrument, which supplies a long felt want among civil and mining engineers, contains within itself, lamp and lantern combined. The Plum- met, which is chambered for the purpose at the top, is the lamp, and all the parts are firmly secured together, giving an absolute solidity to the whole. All the work, being done upon the lathe, is con- centric, securing a perfectly vertical line through the point, the lamp and the point of suspension. The difficulties of protecting the flame from flaring and those arising from the non-adjustment of the point and the flame, which are experienced in the best lamps heretofore constructed, wherein the lamp is suspended by chains, are entirely obviated. To light the lamp it is only necessary to slide up the glass which forms the lantern and apply the match. The conical top of the lantern protects the light against water dropping from the roof of the mine or tunnel. It is admirably adapted for use in mills and manufactories where shafting is laid. Special diploma awarded by the Mechanics' Institute, San Fran- cisco, 1883. Size No. 1, weighs 2% Ibs.; size No. 2, weighs \% Ibs. 84 ILLUSTRATED CATALOGUE OF SURVEYING ANEROID BAROMETERS, WITH VERNIER READING TWO FEET. No. 60 Purveying Barometer, brass case, 5 inch diam- eter, silvered dial, division on raised ring, fixed altitude scale 15,000 feet, vernier scale operated by rack and pinion, reading to one foot, compensated for temperature, adjust- able reading lens, in leather sling case each, $50 ()( No. 61 Surveying Barometer, brass case,Q inch diam- eter, silvered dial, division on raised ring, fixed altitude scale 10,000 feet, vernier scale operated by rack and pinion, reading to five feet, compensated for temperature, adjust- able reading lens, in leather sling case 47 0( J. C. SALA, SAN FRANCISCO ANEROID BAROMETERS. FOR MEASURING HEIGHTS AND ATMOSPHERIC PRESSURE. No. 62 Pocket pattern, bronzed case, 2^ inch diametei, silvered dial, revolving altitude scale from Sooo to 16,000 feet. Revolving altitude scale compensated for temperature. In morocco case, price from $20 to $30 No. 63 Pocket pattern, gilt case, 1^ inch diameter, sil- vered dial, revolving altitude scale 8000 feet, compensated for temperature. In morocco case, price from $10 to $20 86 ILLUSTRATED CATALOGUE OF ACHROMATIC FIELD AND MARINE GLASSES. Manufactured by the Societe d'Optique, Paris. No. 64. Field or Marine Glasses, black kid body with sun- shades, finely japanned or oxidized draw- tubes, cross-bars, tops and trimmings; in sole leather sling case: 21 24 26 lignes. $14.00 16.00 18.00 Manufactured by Bardou, Paris. No. 65. Field or Marine Glasses, black morocco body with sun- shades, oxidized draw-tubes, cross-bars, tops and trimmings; in sole leather sling case: 24 J2I.OO 26 lignes 24.00 No. 66. Field or Marine Glasses, as above, with 12 lenses: 24 26 lignes. $25.00 28.00 J. G. SALA, SAN FRANCISCO ACHROMATIC FIELD AND MARINE GLASSES-Continued. No. 67. Field or Marine Glasses, with jointed cross-bars, afford- ing adjustment for pupillary distance: 2 4 26 iignes. $25.00 28.00 Manufactured by Lemaire, Paris. No. 68. Field or Marine Glasses, superior, U. S. Signal Service, black morocco body with sun-shades, finely black japanned or oxidized draw-tubes, cross-bars, tops and trimmings; in sole leather sling case : 24 26 Iignes. $18.00 20.00 No. 69. Field or Marine Glasses, as above, with jointed cross- bars, affording adjustment for pupillary distance, 26 Iignes $28.00 No. 70. Field or Marine Glasses, black morocco body with sun- shades, black japanned or oxidized draw-tubes, cross-bars, tops and trimmings in morocco sling case : 15 17 19 21 24 26 28 Iignes. $9.00 10.00 11.00 12.00 13.00 14.00 25.00 No. 71. Field or Marine Glasses, as above, with 12 lenses; sole leather case, 26 Iignes $21.00 No. 72. Field or Marine Glasses, black morocco body with sun- shades, black japanned or oxidized draw-tubes, tops and trimmings; jointed cross-bars, affording adjustment for pupillary distance; in sole leather sling case : 24 26 Iignes. $21.00 22.50 No. 73. Field or Marine Glasses, black morocco body with sun- shades, finely black japanned or oxidized draw-tubes, cross-bars and hie tops, compact model, designed to afford large field, in morocco sling case: I5 1 7 19 21 24 26 Iignes. $11.00 12.00 13-00 14-00 15-00 16.00 88 ILLUSTRATED CATALOGUE OF BINOCULAR TELESCOPES, No. 74. These glasses have great power, and where objects are fully illuminated, they are unequaled. They are provided with hinge or joint, and can be adjusted to the different widths of eyes, thereby securing a perfectly even field, and avoiding, when looked through, all strain to the ocular muscles. The performance of a glass of this kind is equal to a spy-glass of very much greater power, because, by the use of both eyes, the field of vision or amount of scenery which a person sees at one time is wonder- fully increased. Complete with sun-shades, case, strap, etc. Binocular Telescope, as above, n lignes $ 50 oo i3 " 55 oo 15 " 65 oo ALUMINUM BINOCULAR TELESCOPES, No. 75. ii lignes, same as above $ 75 oo 13 " " " 85 oo 15 " " : 100 oo 17 " " " 115 oo J. C. SALA, SAN FRANCISCO 8 9 SPY- GLASSES, No. 76. First Quality. 11 Lignes, Equal to One Inch Spy-glasses 3 draws, black morocco body, stitched, burnished brass draw tubes. DIMENSIONS. Full Length, Closed, Inches. Inches. Diameter of Object Glass, Lignes. Magnifying Power, Times. Range, Miles. PRICE. C I/ 5/4 IO 10 5 $2 50 lf>X 6 II 15 6 3 i6X 6 12 15 6 3 50 r; 6^ 13 2O 7 4 oo 634 2O 8 4 50 23 8 16 25 9 6 oo 30 IO 10 30 IO 8 oo Spy-glasses, 4 draws, with sun-shade to extend over object glass; black morocco body, burnished draw tubes. DIM EN}- Full Length, Inches. IONS. Closed, Inches. Diameter of Object Glass, Lignes. Magnifying Power, Times. Range, Miles. PRICE. 36 45'-- I0# 1234 22 25 40 45 H 18 $16 50 23 50 The above are very superior glasses for terrestrial observations, and afford excellent views of the sun, moon, Satellites of Jupiter, etc. To produce the best results, they should be used on a tripod stand. Tripods for any spy-glass, nicely made oo POCKET MAGNIFIERS, No. 77. Rubber case, size of lens i inch diameter ................................ $ 5 i " " ................................ 75 lenses i /s and i # inch diameter ............... i 25 Shell case, size of lens i# inch diameter ................................ T 3 ' " lenses i and i ^ inch diameter .................. i ^o ILLUSTRATED CATALOGUE OF J. C. SAL A, S. F. GOSSAMER AND SILK BAGS. Gossamer or water-proof bag, to cover transit or level in case ) # c i (. #* * ^^ of rain or dust )~ Silk bag, to cover transit, with solid graduations i oo LUBRICANTS. Bottle of fine watch oil, for lubricating transit centers, etc $o 25 " vaseline for lubricating level centers, leveling and ) tangent screws, etc ( UTENSILS FOR CLEANING INSTRUMENTS. Camel's hair brush $o 40 Stiff brush for cleaning screw-threads 40 Chamois-skin for cleaning lenses, centers, etc 50 Stick for cleaning centers 50 ROD LEVEL, No. 78-PRICE $3.50. This contrivance consists of a Universal level and a V shaped handle. The shape of the handle permits one to use the rod level on any round, prismatic or angular pole. TIMBER SCRIBER, No. 79 PRICE $1.25. Tool for surveyors to mark stakes, bearing trees, etc. STEPHENS' COMBINATION RULE, No. 80 PRICE $2.00. ROD LEVEL. IMPROVED CAMERA LUCIDA, No. 81 PRICE $10.00. With double sliding tubes and clamp; in mahogany case. Surveyors' Engineers' Architects' and Draughtsmen's Office Requisites PART B J. C. SALA, SAN FRANCISCO 7O DRAWING MATERIALS. Drawing boards from 75 cents each, for small work, to any size and price desired. Constructed of sound, seasoned wood. Trestles and horses for drawing boards furnished to order. Folding trestles and cases of drawers also furnished. Send for plans and prices. Drawing papers of all standard makes and names, in sheets and rolls. Detail papers, tracing papers, tracing cloth, profile and cross-section paper in sheets and rolls, kept on hand and sent upon order at regular catalogue prices of all dealers. Sample books, with prices, 15 cents. BLUE PRINT PAPERS. Any make of the standard blue print papers can be furnished at the catalogue price of the maker. Also blue print frames and all appliances for the work. To make blue print copies of tracings. As some customers off in the country are called upon for blue print copies occasionally and cannot wait for the supplies to arrive from San Francisco, and besides may not have enough calls for such work to warrant them in keeping a supply on hand at all times, the following directions for making their own paper may be useful. 1st. The paper should be a good quality of book paper. 2cl. The Mixture. This consists of equal parts, by weight, of citrate of iron and ammonia, and red prussiate of potash. These may be procured from any druggist. They are mixed in the proper* one ounce of citrate of iron and ammonia and one ounce of red pn siate of potash to eight ounces of water. Put in a stone bottle (to 1 94 ILLUSTRATED CATALOGUE OF from the light) and shake well. In ten minutes they will be dissolved. 3d. Lay the paper which is to be treated, on a smooth table or board. Pour some of the sensitizing solution in a shallow dish, as a plate or saucer, and with a broad brush like a soft copying-press brush, apply a good even coating of the solution to the paper. When the paper is coated, tack it to a board and put it in a dark place to dry, an operation which wall take about an hour. 4th. To Print. Upon a smooth board tack two or three thick- nesses of flannel or blanket, and be careful that they are not wrinkled. Lay on the cloth the sheet of sensitized paper with the coated surface up; upon this lay the tracing, and great care must be exercised that the paper and tracing are also very smooth, as a wrinkle will spoil the work. Upon the tracing, lay a piece of heavy plate glass. The fore- going operations must be conducted in a dark room. The glass must be heavy to keep the paper smooth. After the glass is in position, bring the board out to the light and put it in the place it is to remain while printing. 5th. Within an hour or two of noon during the summer time, from six to ten minutes will suffice for an exposure. Karlier or later in the morning it will take longer to make a good print, and if the day is cloudy or the drawing cannot be exposed directly to the sun, it may take from half an hour to one or two hours to secure a good print. Experience will soon enable one to do good work. 6th. Washing. After the print has been exposed a sufficient time, take it from under the glass and place in a sink or shallow box filled with cold water. Let it soak for a few minutes and then wash it thoroughly. The lines of the drawing, faintly visible up to this time, will appear in clear white lines upon a blue ground. After washing, tack it up against a wall or hang by the corners from a line to dry. The operation is then finished. 7th. To write with a white line upon a blue print, use a solution of common soda with an ordinary pen. Papers and material also kept for positive black printing processes, which some prefer to bhie prints. J. C. SAI.A, SAN FRANCISCO 95 Engineers' Field Books for transit, level, topography and stadia work, kept on hand or made to order at regular catalogue prices. Lead Pencils of all the best makes furnished when called for. THE PLANIMETER, No. 82. The polar planimeter is used for computing with rapidity and accuracy, the area of any figure, how irregular it ever may be, such as railroad profiles, indicator diagrams, plots of ground, etc., etc., and is of great value to engineers and others on account of its saving in time and labor. Amsler's polar planimeter, German silver, in case $27 50 Pantographs of any make can be furnished to order at regular prices. PROTRACTORS, No. 83-PRICE FROM $1.00 to $6.00. Plain circular and semi-circular protractors, German silver, bras* or horn, divided to #, %,. 3ti4 single degree. 9 6 ILLUSTRATED CATALOGUE OF KERN'S SWISS PROTRACTORS, WITH ARM AND VERNIER, No. 84. Semi-circular German silver Protractor, 5^ -inch, divided to ) */z degrees, with arm and vernier, reading to 3 minutes... j Semi-circular German silver Protractor, 8-inch, divided to ^ I degrees, with arm and vernier, reading to 1 minute ( Semi-circular German silver Protractor, 10-inch, divided to ^ ( degrees, with arm and vernier, reading to 1 minute j Circular German silver Protractor, 5^ -inch, divided to */, / degrees, with arm and vernier, reading to 3 minutes ( Circular German silver Protractor, 8-inch, divided to ^ degrees, with arm and vernier, reading to 1 minute Circular German silver Protractor, 10-inch, divided to ^ $n oo 14 oo 17 oo 14 oo 1 6 oo TO OO degrees, with arm and vernier, reading to 1 minute $ Morocco silk velvet-lined cases for above, $3.50 to $4.50. DRAUGHTSMEN'S PROTRACTORS, No. 85. This Protractor is made from V l6 -inch sheet steel and is light and durable. The length of the blade is 8>4 inches. The graduations read to degrees and the vernier reads to 5 minutes. This Protractor is chiefly used in connection with a T square or straight edge. It can be quickly and accurately set by hand to any J. C. SALA, SAN FRANCISCO 97 angle. A lever is, however, provided as of possible advantage in obtaining very fine settings. There are no projections on -ither face of the Protractor, and, consequently, it can be used on either edge of the blade or either side up. This makes it particularly convenient in dividing circles, trans- ferring angles, drawing oblique lines at right angles to each other, or laying off given angles each side of a vertical or horizontal line without changing the setting. In many instances the Protractor takes the place of the ordinary 4.V:lc--R.'e and (iO-degree triangle, and it is also used as an extension to the T square when the work is beyond the end of the blade of the square. Draughtsmen's Protractor, in morocco case, velvet-lined ........... $9 oo no case ......................................... 7 50 Boxwood and Ivory Protractors. catalogue prices. Any make at regular k j, A J 'J IP .jo iji jg j 1 i 5J5 5(6 5 HH cp fflffl ^ ' n 5 * 13 2 1 3/tj. 5 L^ST 1 91 1 9 i L L' 03 'IN M %I FLAT SCALES, No. 86. Ivory and boxwood flat chain scales, for engineers and architects, from $1.00 to $8.00. Special divided scales made to order. TRIANGULAR SCALES, No. 87. Patent Metallic Scales, 12 inches long, for architects or engineers, price $:-J.OO. Boxwood Scales, for architects or engineers, 12-inch $1.50; 18-inch $2..">0; 24-inch $4.25. Triangular Scale Guard, 25 cents. 98 ILLUSTRATED CATALOGUE OF MANNHEIM SLIDE RULE, No. 88-PRICE $4.50. 10-inch long, divided on celluloid tacing, with brass indicator, also directions for using. STADIA SLIDE RULE, No. 89 PRICE $13.50. 20-inch, celluloid face. STRAIGHT EDGES, No. 90. Steel nickel plated: 24 30 36 42 48 60 72 inches $2.00 3.00 4.00 5-oo 6.00 8.50 12. oo Celluloid edged: 24 30 36 42 48 inches $1.00 1.25 1.50 1.80 2.20 T SQUARES, WOOD, No. 91. According to size, from ........................................... 25cts. to $1.50 With shifting head, according to size, from .................. $1.25 " 3.00 TRIANGLES, No. 92. Steel nickel plated, 45: 8 10 12 inches $4.25 5.50 6.50 Steel nickel plated, 30 and 60: 8 10 15 inches $3.85 4.25 6.50 PARALLEL RULERS, No. 93. Ebony folding: 6 9 12 15 18 24 inches 3oc 55c ysc 9oc $1.10 2.20 Rolling brass: 12 15 18 inches $9.00 10.50 12.00 Rolling ebony: 12 15 18 inches $5.00 6.50 7.50 J. C. SALA, SAN FRANCISCO 99 Drawing instruments, colors, brushes, and all the one thousand and one little office necessities for engineers', surveyors' and draughtsmen's use, kept constantly on hand and furnished on demand. Prices the same as all dealers' catalogues. Mention name of dealer, date of catalogue, name and number of article wanted when ordering. IN OTI C I am prepared to manufacture on short notice, to order, any scientific instruments applied to astronomy, navigation, physics, or chem- istry appertaining to my line of business. J. C. SALA. Miscellaneous Scientific Instruments . PART C J. C. SALA, SAN FRANCISCO I0 3 ASTRONOMICAL TELESCOPE, No. 94 PRICES $50 to $200. Body with finder and movements of highly finished lacquered brass, rack and pinion for adjustment of focus; object-glass 3;^ inches in diameter, two terrestrial eye-pieces with sun-glass powers of 75, 100 and lo() diameters; packed in strong walnut case, with lock and key. The telescope is mounted upon a very fine polished, firm mahogany tripod stand, with folding legs, and can be adjusted to any desired height by a rack and pinion operated by a crank. Heliographs for signaling by day or night, complete $45.00 IO4 ILLUSTRATED CATALOGUE OF SALA'S STANDARD RAIN GAUGE, No. 95 PRICE $3.00. The utility of knowing the rainfall of any locality is sufficiently obvious, and little need be said upon the subject. The rain gauge should be in the hands of every gardener and farmer. In the management of out-door plants and crops, as well as in the maintenance of cisterns and tanks for the supply of water, a rain gauge is a valuable assistant. By its use the gardener will be guided in judging how far the supply of moisture to the earth is needed, and he will also see how beneficial is even a hasty shower to growing plants when he considers that a fall of rain measuring the tenth of an inch in depth corresponds to the deposit of about forty hogshead per acre, The study of the rainfall of a country is of considerable interest to agricultur- alists. The health and increase of domestic animals, the development of the productions of the land, as well as the daily labors of the farmer are dependent upon the excess or deficiency of rain. The statistics of rainfall are not only valuable and interesting, from a meteorological point of view and for agricultural purposes, but are also highly important in connection with sanitary arrangements for towns and engineering operations; this is especially evident to the hydraulic engineer. As rain is an important source of water supply to rivers, canals and reservoirs, it is evident that a knowledge of the probable fall of any season or month at a given place, as furnished by averages of the observations of former years, will be the data upon which the engineer will base his plans for providing for floods or droughts, while the measurement of the actual quantity which has just fallen, as gathered J. C. SALA, SAN FRANCISCO IQ{ . from indications of a series of gauges, will suggest to him the precau- tions to adopt, either to economize or to conduct away the inflowing waters. This rain gauge is made of metal, is simple, and cannot get out of order. It consists of four pieces: a. The overflow, a galvanized iron cylinder 12 inches long and 3 inches in diameter, holding 10 inches of rain. b. The copper receiver, which catches all the rain to be measured. c. The brass measuring cylinder connecting with the copper receiver. d. The black walnut measuring rod having ten inches divided into one hundred parts; measuring as one inch the rainfall to that degree of accuracy. ch, mounted and r ~,. graduated on neatly carved, solid box- ' wood back J Thermometers and Hydrometers of all descrip- tion and sizes. Papers and Tables PART D IN Selecting Tables, I have omitted all those contained in either the " Manual of Instructions " pub- lished by the General Land Office of the United States or those found in the Nautical Almanacs. J. C. SALA. J. C. SALA, SAN FRANCISCO THE SAEGMULLER SOLAR ATTACHMENT. Patented Ma> 3, 1881. J. C. SALA, AGENT. This attachment to the regular engineer's transit, by means of which the astronomical meridian may be obtained in a few minutes with an accuracy scarcely thought to be possible, has met with such success that it bids fair to supersede all other methods for the determi- nation of the meridian by means of engineering instruments. The transit has come to be the universal instrument for the engineer, and will be for the surveyor sooner or later, and the attach- ment of the solar apparatus to the transit has thus become a necessity. Since its first introduction, this attachment has been greatly improved, and as now made, is well nigh perfect. Attached to any transit which possesses a telescope, level and a vertical circle, it will give the meridian within the nearest minute. By using instruments which have a finer graduated vertical circle and better levels than are usually found on transits, the meridian can be determined with greater accuracy still. Advantages of the "Saegmuller Solar Attachment" over the old First. It is more accurate. Second. It is simpler and easier of adjustment. Third. It can be used when the sun is partly obscured by clouds, when the ordinary " solar " fails altogether. Fourth. It can be used where the sun is quite close to the meridian. Fifth. The time can be obtained with it reliable to within a few seconds with perfect ease. Sixth. It can be used as a vertical sighting telescope. It is as superior to all forms hitherto used, as the transit is to the ordinary compass, or as a telescope is to common sights. The sights of an ordinary solar compass consist merely of a small lens and a piece of silver with lines ruled on it placed in its focus. This 110 ttLUSTRATED CATALOGUE OF is simply a very, primitive telescope, since the exact coincidence of tin sun's image with the lines has to be determined by the unaided eye, o at best with a simple magnifying glass. That far greater precision cat be attained by means of a suitable telescope is obvious; in fact, th< power of the solar telescope is in keeping with the transit telescope, a: it should be. A glance at the cut will show that the ' ' Saegmuller Solar Attach ment ' ' is far simpler than the ordinary form. By raising or depress ing, it can be set to north or south declination. To effect this with th< ordinary solar compass, two sets of primitive telescopes one answering for north, the other for south declination are required, which an difficult to adjust. The addition of the level on the solar telescop< dispenses with the declination arc altogether, the arc or circle on th< transit also serving for that purpose in conjunction with it. Th( ' ' Saegmuller Solar Attachment " is in fact the only one which shoulc be used in connection with a transit instrument. // solves the sola* problem, as has been attested by leading astronomers and engineer* who have used it. Prof. J. B. Johnson, of Washington University, St. Louis, Mo. has given it a thorough test, and writes as follows: "In order to determine just what accuracy was possible with a Saegmulle: Solar Attachment, I spent two days in making observations on a line whose azi muth had been determined by observations on two nights on Polaris at elonga tion, the instrument being reversed to eliminate errors of adjustment. Forty five observations were made with the solar attachment on Oct. 24, 1885, from 9 t< 10 A. M., and from 1.30 to 4 P. M., and on Nov. 7, forty-two observations betweer the same hours. "On the first day's work the latitude used was that obtained by an ob servation on the sun at its meridian passage, being 38 39', and the mean azimutt was 20 seconds in error. On the second day, the instrument having been more carefully adjusted, the latitude used was 38 37', which was supposed to be aboul the true latitude of the point of observation, which was the corner of Park and Jefferson avenues in this city. It was afterwards found this latitude was 38 37' 15", as referred to Washington University Observatory, so that when the mean azimuth of the line was corrected for this I5 X/ error in latitude it agreed exactly with the stellar azimuth of the line, which might have been io x/ or 15' ' in error. On the first day all the readings were taken without a reading glass, there being four circle readings to each result. On the second day a glass was used. " On the first day the maximum error was 4 minutes, the average error was 0.8 minute, and the 'probable error of a single observation' was also 0.8 minute. On the second day the maximum error was 2.7 minutes, the average J. C. SALA, SAN FRANCISCO III error was I minute, and the ' probable error of a single observation ' was 0.86 minute. The time required for a single observation is from three to five minutes. " I believe this accuracy is attainable in actual practice, as no greater care was taken in the adjustment or handling of the instrument than should be exer- cised in the field. ' ' The transit has come to be the universal instrument for the engineer, and should be for the surveyor; so it is more desirable to have the solar apparatus attached to the transit than to have a separate instrument. The principal advan- tages of this attachment are : " i. Its simplicity. "2. Its accuracy of pointing, being furnished with a telescope which is accurately set on the sun's disk. "3. In its providing that all angles be set off on the vertical and horizontal limbs of the transit, thus eliminating the eccentricity and other inaccuracies usually found in attachment circles or arcs. ' ' 4. Its small cost. " It is also readily removed and replaced without affecting its adjustments, and is out of the way in handling and reversing the telescope. It may be at- tached to any transit." SAEGMULLER SOLAR ATTACHMENT. The above cut represents the improved "Saegmuller Solar At- tachment" as now made. It consists essentially of a small telescope and level, the telescope being mounted in standards, in which it can b elevated or depressed. The standard revolves around an axis, c the polar axis, which is fastened to the telescope axis of the trans strument. The telescope called the - Solar Telescope" can thus moved in altitude and azimuth. Two pointers attached to the telescope 112 ILLUSTRATED CATALOGUE OF to approximately set the instrument are so adjusted that when th( shadow of the one is thrown on the other the sun will appear in the field of view. Adjustment of the Apparatus. 1. The transit must be in perfect adjustment, especially th( levels on the telescope and the plates ; the cross axis of the telescop< should be exactly horizontal, and the index error of the vertical circl< carefully determined. 2. The Polar axis must be at right angles to the line of colli mation and horizontal axis of main telescope. To effect this, level the intstrument carefully and bring the bubbl< of each telescope level to the middle of its scale. Revolve the sola- around its polar axis, and if the bubble remains central the adjustmen is complete. If not, correct half the movement by the adjusting screw! at the base of the polar axis, and the other half by moving the solai telescope on its horizontal axis. 3. The line of Collimation of the solar telescope and the axis Oj its level must be parallel. To effect this, bring both telescopes in the same vertical plane and both bubbles to the middle of their scales. Observe a mark throng! the transit telescope, and note whether the solar telescope points to mark above this, equal to the distance between the horizontal axis o the two telescopes. If it does not bisect this mark, move the cross wires by means of the screws until it does. Generally the small level has nc adjustments and the parallelism is effected only by moving the cross- hairs. The adjustments of the transit and the solar should be fre- quently examined, and kept as nearly perfect as possible. Directions for Using the Attachment. First. Take the declination of the sun as given in the Nautical Almanac for the given day, and correct it for refraction and hourly change. Incline the transit telescope until this amount is indicated by J. C. SALA, SAN FRANCISCO its vertical arc. If the declination of the sun is north, depress it ; if south, elevate it. Without disturbing the position of the transit tele- scope, bring the solar telescope into the vertical plane of the large telescope and to a horizontal position by means of its level. The two telescopes will then form an angle which equals the amount of the decli- nation, and the inclination of the solar telescope to its polar axis will be equal to the polar distance of the sun. Second. Without disturbing the relative positions of the two telescopes, incline them and set the vernier to the co-latitude of the place. By moving the transit and the ' * Solar Attachment ' ' around their respective vertical axis, the image of the sun will be brought into the field of the solar telescope, and after accurately bi- secting it the transit telescope must be in the meri- dian, and the compass-needle indicates its deviation at that place. The vertical axis of the " Solar Attachment " will then point to the pole, the apparatus being in fact a small equatorial. Time and azimuth are calculated from an ob- served altitude of the sun by solving the spherical triangle formed by the sun, the pole, and the zenith of the place. The three sides, S P, P Z, Z S, complements respectively of the declination, latitude, and altitude, are given, and we hence deduce S P Z, the hour angle, from apparent noon, and P Z S, the azimuth of the sun. The "Solar Attachment" solves the same spherical triangle by construction, for the second process brings the vertical axis of the solar telescope to the required distance, Z P, from the zenith, while the first brings it to the required distance, S P, from the sun. Observation for Time. If the two telescopes, both being in position-one in the meri- dian, and the other pointing to the sun -are now turned horizontal axis, the vertical remaining undisturbed, until each ILLUSTRATED CATALOGUE OF the angle between their directions (found by sighting on a distant object) is S P Z, the time from apparent noon. This gives an easy observation for correction of time-piece, reli- able to within a tew seconds. To Obtain the Latitude with the " Saegmuller Solar Attachment." L,evel the transit carefully and point the telescope toward the south and elevate or depress the object end, according as the declina- tion of the sun is south or north, an amount equal to the declination. Bring the solar telescope into the vertical plane of the main tele- scope, level it carefully and clamp it. With the solar telescope observe the sun a few minutes before its culmination ; bring its image between the two horizontal wires by moving the transit telescope in altitude and azimuth, and keep it so by the slow motion screws until the sun ceases to rise. Then take the reading of the vertical arc, correct for re- fraction due to altitude by the table below. Subtract the result from 90, and the remainder is the latitude sought. Mean Refraction. Barometer 30 inches, Fahrenheit Thermometer 50. Altitude. Refraction. 1 Altitude. Refraction. 10 5' 19" 20 2' 39" II 4 5i 25 2 04 12 4 27 30 I 41 13 4 07 35 I 23 14 3 49 40 I 09 15 3 34 45 58 16 3 20 50 49 17 3 08 60 34 18 2 57 70 21 19 2 48 80 10 The following table, computed by Prof. Johnson, C. E., Wash- ington University, St. L/ouis, will be found of considerable value in solar compass work: J. C. SALA, SAN FRANCISCO " This table is valuable in indicating the errors to which the work is liable at different hours of the day and for different latitudes, as well as serving to cor- rect the observed bearings of lines when it afterwards appears that a wrong lati- tude or declination has been used. Thus on the first day's observations I used a latitude in the forenoon of 38 37', but when I came to make the meridian obser- vation for latitude I found the instrument gave 38 39'. This was the latitude that should have been used, so I corrected the morning's observations for two minutes error in latitude by this table. "It is evident that if the instrument is out of adjustment the latitude found by a meridian observation will be in error; but if this observed latitude be used in setting off the co-latitude the instrumental error is eliminated. There- fore always use for the co-latitude that given by the instrument itself in a meri- dian observation." Errors in Azimuth (by Solar Compass) for i mm. Error in Declination or Latitude. HOUR. FOR i MIN. ERROR IN DECLINATION. FOR i MIN. ERROR IN LATITUDE. Lat. 30 Lat. 40 Lat. 50 Lat. 30 Lat. 40 Lat. 50 II. 30 A.M. ) 12. 30 P.M. \ MIN. 8.85 MIN. 10.00 MIN. I2.9O MIN. 8.77 MIN. 9.92 MIN. 11.80 I 1. 00 A.M. \ 1. 00 P.M. i 4.46 5-05 6.01 4-33 4.87 5.80 IO.OOA.M. / 2.00 P.M. ( 2.31 2.6l 3-H 2.00 2.26 2.70 Q.OOA.M. ) 3.00 P.M. ( 1.63 1.85 2.20 1.15 1.30 1.56 8.00A.M. J 4.00 P.M. j i-34 '$ I. 80 0.67 0.75 0.90 7. 00 A.M. / 5.00 P.M. \ 1.20 i-35 1.61 0.31 0-35 0-37 6.00A.M. / 6.00 P.M. $ I-I5 1.30 1.56 o.oo o.oo O.OO NoT ,-A zim uths observed with erroneous deduction or co rected by means of this table by observing that for tlv e of co the azimuth of any line from Ike south point ^ the d.rec ,on S. W. N smalt in ^forenoon and too large in the "t' e 00 ar minute of error in the altitude of the line of si*ht. T ^ ^ too low. n6 ILLUSTRATED CATALOGUE OF Correction for Refraction. This correction is applied to the declination of the sun, and is equal to the refraction-correction of the sun's observed altitude multi- plied by the cosine of the angle which the sun makes between the decimation -circle and the vertical. In order to reduce the refraction-correction to the simplest possible form, we have added a separate column to the ephemeris containing them, which we publish every year. They are thus brought in imme- diate juxtaposition with the decimation angle, and we think the arrangement will be appreciated by those who use the Solar Attach- ment. Latitude Coefficients. LAT. COEFF. LAT. COEFF. LAT. COEFF. LAT. COEFF. 15 30 27 -56 39 .96 5i 47 16 32 28 59 40 .00 52 53 *7 34 29 .62 4i .04 53 58 18 .36 30 65 42 .08 54 .64 19 38 3i .68 43 .12 55 .70 20 .40 32 7i 44 .16 56 .76 21 .42 33 75 45 .20 57 .82 22 44 34 .78 46 .24 58 .88 23 .46 35 . .82 47 .29 59 94 24 .48 36 85 48 33 60 2.00 25 50 37 89 49 1.38 26 53 38 92 50 1.42 J. C. SALA, SAN FRANCISCO Refraction Correction, Lat. 40. January. February. March. April. May. Juue. 1 2 lh.1 58 2 2 16 3 3 04 1 2 1 2 lh 1 03 2 1 10 3 1 27 1 3 3h 57 4 i 19 5 2 18 1 2 lh.0 28 2 32 3 39 1 2 5li I 11 3 4 4 6 23 1 1 54 3 4 lh.1 26 2 I 37 3 4 4 2 06 5 4 39 1 * 1 39 2 44 3 4 55 5 1 30 3 4 5 1 19 2 23 3 30 5 2 2 11 5 3 2 04 5 1 59 6 3 54 4 1 26 6 4 43 6 7 3 2 59 7 4 3 21 6 7 2 I 06 3 1 21 7 8 4 I 14 5 2 06 5 6 2 30 3 37 7 5 I 10 8 9 10 11 12 13 4 6 01 1 I 51 2 2 07 3 2 51 4 5 40 8 9 10 11 12 1 1 21 2 1 31 3 1 56 4 3 04 8 9 10 11 12 4 1 56 5 4 04 1 55 2 I 02 3 1 15 9 10 11 12 13 ' 1 36 2 41 3 51 4 1 10 5 1 58 7 9 10 11 12 4 53 5 1 26 1 25 2 29 3 36 4 51 8 9 10 11 12 13 I IS 2 22 3 29 4 43 5 1 09 1 18 14 1 1 46 13 14 1 1 16 2 1 25 13 14 4 I 47 5 3 34 14 15 1 34 2 38 13 14 5 1 22 1 23 14 15 2 22 3 29 15 16 17 18 19 20 21 22 23 24 25 2 2 01 3 2 40 4 5 00 1 1 42 2 1 56 3 2 31 4 4 35 1 1 37 2 1 58 15 16 17 18 19 20 21 22 23 24 25 3 1 48 4 2 47 5 8 39 1 1 12 2 1 20 3 1 40 4 2 31 5 6 49 I 1 07 2 1 15 3 1 33 15 16 17 18 19 20 21 22 23 24 1 052 2 58 3 1 10 4 1 39 5 3 08 1 48 2 54 3 1 05 4 132 5 2 51 16 17 18 19 20 21 22 23 24 25 26 3 48 4 1 06 5 1 49 1 32 2 36 3 45 4 1 02 5 1 42 1 30 2 34 3 42 15 16 17 18 19 20 21 22 23 24 25 26 2 27 3 34 4 49 5 1 18 1 22 2 026 3 33 4 47 5 1 15 1 21 2 25 3 32 16 17 18 19 20 21 22 23 24 25 26 4 42 5 . 1 08 1 18 2 22 3 28 4 42 5 1 08 1 18 2 22 3 29 4 42 2 26 4 2 18 25 1 45 27 4 58 ! 27 4 40 27 5 1 08 27 3 2 22 27 5h.5 28 26 2 50 28 5 1 36 28 5 1 13 28 29 4 4 07 1 1 32 28 27 28 3 1 01 4 1 25 29 30 1 28 1 29 1 20 2h 32 i 2 24 28 29 1 18 2 22 3 29 30 2 1 44 'ft 5 2 34 30 3 31 30 4h.O 43 3 -2 13 30 1 42 4 44 31 4h.3 41 31 2h.O 47 31 5h.l 11 July August. September. October. November. December. 5h.l 09 1 1 lh.0 39 1 lh.0 59 1 2h.3 21 1 lh 1 54 2 2 44 2 2 1 06 2 3 13 57 9 2 2 11 1 19 2 23 3 3<> 2 3 4 lh 26 2 30 3 37 3 4 5 3 54 4 1 14 5 2 08 3 J 4 1 56 5 4 04 3 4 5 4 5 1 1 32 : 3 259 3 4 6 01 4 | 5 4 43 5 4 53 f> 1 42 6 I 1 03 6 2 i 44 5 1 1 58 5 1 10 6 5 1 26 i 7 2 47 7 2 1 10 7 3 2 13 6 2 2 16 1 20 7 j 1 028 ^ 3 57 4 1 19 8 9 3 1 27 4 2 or, 8 9 4 3 41 5 7 8 3 3 04 4 6 23 2 24 3 31 4 44 5 1 11 1 21 2 25 3 32 4 46 5 1 13 1 22 2 26 3 33 4 47 5 1 15 1 23 2 27 3 34 4 49 5 1 18 1 25 ' 2 29 3 36 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 2 32 3 39 4 55 5 1 30 1 30 2 34 3 42 4 58 5 1 36 1 32 2 36 3 45 4 1 02 5 1 42 1 34 2 38 3 48 4 1 06 5 1 49 1 36 2 41 3 51 10 11 12 13 14 15 16 17 18 19 ''O 21 22 23 24 25 26 27 28 29 30 5 2 18 1 45 2 50 3 1 01 4 '1 25 5 2 34 1 48 2 54 3 105 4 1 32 5 2 51 1 52 2 58 3 1 10 4 1 39 5 3 08 1 55 2 1 02 3 1 15 4 I 47 5h.3 34 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 5 4 39 1 1 07 2 1 15 3 1 33 4 2 18 5 5 39 1 1 12 2 1 20 3 1 40 4 2 31 5 6 29 1 1 16 2 1 25 3 1 48 4 2 47 5 8 39 1 1 21 2 1 31 3 1 56 4 3 04 5 11 01 lh.1 26 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 M 1 1 37 2 150 3 2 22 4 4 07 5 1 1 42 2 1 56 3 2 31 4 4 35 5 1 1 46 2 2 01 3 2 40 4 4 59 5 1 1 50 2 2 06 3 2 49 4 5 33 5h. 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 5 1 2 00 2 2 19 3 3 09 4 6 38 5 1 2 01 2 2 20 3 3 11 4 6 47 5 1 2 01 2 2 20 3 3 11 4 6 49 5 1 2 00 2 2 19 3 3 09 4 6 43 5h. 4 51 30 4 1 10 31 1 37 11 5h.l 22 31 5h.l 58 I 2 04 M Il8 ILLUSTRATED CATALOGUE OF The Preparation of the Declination Settings for a Day's Work. The Solar Ephemeris gives the declination of the sun for the given day, for Greenwich mean noon. Since all points in America are west of Greenwich, by 5, 6, 7, or 8 hours, the declination found in the ephemeris is the declination at the given place at 7, 6, 5, or 4 o'clock A. M., of the same date, according as the place lies in the "Eastern," ''Central," " Mountain," or " Western Time " belts respectively. The column headed ' ' Refraction Correction ' ' gives the cor- rection to be made to the declination, for refraction, for any point whose latitude is 40. If the latitude is more or less than 40 these cor- rections are to be multiplied by the corresponding coefficients given in the table of "Latitude Coefficients," p. 116. Thus the refraction cor- rections in latitude 30 are 65 hundredths, and those of 50 142 hun- dredths of the corresponding ones in latitude 40. There is a slight error in the use of these latitude coefficients, but the maximum error will not amount to over 15", except when the sun is very near the horizon, and then any refraction becomes very uncertain. All refraction tables are made out for the mean, or average, refraction, whereas the actual refraction at any particular time and place may not be more than one- half, or as much as twice the mean refraction, with small altitudes. The errors made in the use of these latitude coefficients are, therefore, very small as compared with the errors resulting from the use of the mean, rather than unknown actual refraction which affects any given observation. Example I. Let it be required to prepare a table of declinations for a point whose latitude is 38 30', and which lies in the " Central Time " belt, for April 5, 1890. Since the time is 6 hours earlier than that at Greenwich, the declination given in the ephemeris is the declination here at 6 A. M. of same date. This is found to be + 6 9 ; 57 /; . To this must be added J. C. SALA, SAN FRANCISCO the hourly change, which is also plus, and equal to 56 ".83. The lati- tude coefficient is 0.94. The following table may now be made out : Declination Settings for April 5, 1830, Lat. jD the correction to the horizontal angle, as found in the read- ing of the instrument, and the line bisecting the sum of these two angles will be the true meridian. TABLE OF CORRECTIONS. I.ut, 8 32| 0.18 0.18 0.19 M 86 86 :<7" tap ayo 400 41 o 42 430 44 45 1 4<; > 47" 480 4'J ' 0.19 0.19 0-19 0.20 0.20 0.20 0.20 0.21 0.21 0.21 0.22 0.22 0.23 0.23 0.23 8t 9 0.17 I 0.17 0.18 0.17 0.18 0.17 0.18 018 0.18 0.19 0.19 0.19 0.19 0.20 0.20 0.20 0.21 0.21 0.22 0.22 0.22 0.17 0.17 0.18 0.18 0.18 0.18 0.19 0.19 0.19 0.20 0.20 0.20 0.21 0.21 0.22 9i 0.16 0.16 0-17 0.17 0.17 0.17 0.17 0.18 0.18 0.18 0.18 0.19 0.19 0.19 0.20 0.20 0.20 0.21 10 0.16 0.16 0.16 0.16 0.16 0.17 0.17 0.17 0.17 0.18 0.18 0.18 0.19 0.19 0.20 0.20 lOi 0.15 0.16 0.16 0.16 0.16 0.16 0.17 0.17 0.17 0.17 0.18 0.18 0.18 0.18 0.19 0.19 0.20 0.20 11 0.15 0.15 0.16 0.16 0.16 0.16 0.16 0.17 0-17 0.17 0-17 0.18 0.18 0.18 0.19 0.19 0.19 0.20 lit 0.14 0.15 0.15 0.15 0.15 0.16 0.16 0.16 0.16 0.17 0.17 0.17 0.18 0.18 0.18 0.19 0.19 0.19 jgPSuostract the product of the multiplication between December 22d J and June 22d. |^- Add the product of the multiplication between June 22d and Dec. 22d. EXAMPLE I. May 24th, 1881, 8:30 A.M., at San Francisco, in Jat. 37 deg.48min. north, I took the altitude of the sun's image; and seven hours afterwards, at 3:30 P.M. I had the same altitude. The horizontal angle between the two observations mea- sured 168 deg. 33 min., and the hourly differences In the sun's declination in the ephem- eris was 27-46 seconds. The tabular number for lat. 38deg. and 8:30 A.M. is 0.19 ; hence correction is : 27.46 x 0.19 gives 5 minutes ; horizontal angle is 168 deg. 33 min., from which deduct 5 min., leaving 168 deg. 28 min., which divided by two gives 84 deg. 14 min. for the true meridian. EXAMPLE II. Sept. 10th, 1881, at 11 o'clock A.M., at the same place of observa- tion, the horizontal angle measured at 1 P.M. 52 deg 41 min.; the hourly difference in the sun's declination was 56.98 seconds. The tabular number for 38 deg. and 11 A.M.is 0.16; hence correction is: 56.98 x 0.16 gives 9 minutes; horizontal angle is 52 deg 41 min., to wtuch add 9 min., making 52 deg. 50 min., which divided by two gives 26 deg. 25 min. for the Jrue meridian. After establishing the line on the ground, the whole manipulation is finished. 144 ILLUSTRATED CATALOGUE OF TABLE Of Refractions la Declination for Solar-Compasses and Solar-Transits. Plus: By SUN'S DECLINATIONS NOKTH, From March 22d to Sept. 22d, add; t April. \ For Hours Sun's Declinations in Nautical Aim. *> V from I \ Lati. Me:id. .+ 20 + 15 , + 10 + 5 < May. \ 30 1. 10 15 21 27 ( \ n a- 14 19 25 31 ( _ \ " 3. 20 26 32 39 ( \ \ ' 4. 32 39 46 52 June. 35 L 2. 15 20 21 25 27 32 33 38 *' 3. 26 33 39 47 ** 4. 39 47 56 1 06 400 1. 21 27 33 40 July r. 2. 3. 25 33 32 40 39 48 46 57 /. ** 4. 47 55 1 05 1 18 ) 45 1. 27 33 40 48 / " 2. 32 39 46 52 / M 3. 4. 40 54 47 1 02 56 1 14 1 06 ) 1 32 , v 500 1. 33 40 48 57 2 38 46 55 1 06 / " 3.' 4. 47 1 00 56 1 45 1 06 2 00 1 20 ) 3 00 ( -22d- ' / Minus: / . 1 Oct BY SUN'S DECLINATIONS SOUTH, From Sept. 22d to March 22d, substracl : ( For Hours Sun's Declinations in Nautical Aim. , / ^~ Lati. from Me rid. - 50 - 100 - 150 - 200 / ! Nov. / // / // / // / // ( / 30 1. 40 48 56 1 00 > / 2. 46 54 1 10 1 18 V / u 3. 55 1 06 1 18 1 36 C 1 Dec. " 4. 1 19 1 35 1 57 229 C 35 1. , 48 57 1 06 1 20 \ M 2. ; 55 1 i 04 1 18 1 34 < " 3. 06 1 20 1 40 2 00 \ ** 4. 40 2 00 2 30 3 30 < Jan. 400 1. 00 1 08 1 30 1 40 ( 2. 08 1 20 1 36 2 00 f \ " 3. 20 1 40 2 00 2 40 ' \ * 4- 2 00 2 30 3 20 5 00 ( \ Feb. 450 . 1. 1 08 1 30 1 40 2 00 ( \ 2. 1 20 1 40 2 00 2 30 < \ i: - 3. 1 40 2 00 2 36 3 30 < \ " 4. 2 20 3 00 4 40 8 00 ( \ March. 500 I. 1 30 1 40 2 00 2 40 \ " 2. 1 36 2 00 2 30 3 15 X i -22d- I! 3. 4. 2 30 3 00 2 45 4 30 3 30 7 00 5 00 15 00 J. C. SALA, SAN FRANCISCO 145 TABLE. Of the increase or decrease of the Sun's Declination for hourly Differences from 5 seconds to 60 seconds, and from three to twelve hours of time. 45 515 57 3 1 . 1 45 4 K 5 !. 6 h. 7 h. 8h. 9 h. 10 h. 11 h. 12 h. 20 25 30 35 40 45 50 55 1 0( 24 30 36 42 48 54 1 00 1 06 1 li 28 35 42 49 56 1 03 1 10 1 17 1 2' 32 40 48 56 1 04 1 12 1 20 1 28 1 3( 3G 45 54 1 03 1 12 1 21 1 30 1 39 1 4 40 50 1 00 1 10 1 20 1 30 1 40 1 50 2 44 55 1 00 1 17 1 28 1 39 1 50 2 01 2 1 48 1 00 12 1 24 1 3C 1 48 2 00 2 12 2 2 52 1 05 18 1 31 1 44 1 57 2 10 2 23 2 3 56 10 24 1 38 1 52 2 06 2 20 2 34 2 4 1 00 15 30 1 45 2 00 2 15 2 30 2 45 3 1 04 20 36 1 52 2 08 2 24 2 40 2 56 3 1 I 08 25 42 1 59 2 16 2 33 2 50 3 07 3 2 1 12 30 48 2 06 2 24 2 42 3 00 3 18 3 3 1 16 35 54 2 13 2 32 2 51 3 10 3 29 3 4 1 20 40 2 00 2 20 2 40 3 00 3 20 3 40 4 1 24 1 45 2 06 2 27 2 48 3 09 3 30 3 51 4 1 1 28 1 50 2 12 2 34 2 56 3 18 3 40 02 4 2 1 32 1 55 2 18 2 41 3 04 3 27 3 50 13 4 3 1 36 2 00 2 24 2 48 3 12 3 36 4 00 24 4 4 1 40 2 05 2 30 2 55 3 20 3 45 4 10 35 5 1 44 2 10 2 36 3 02 3 28 3 54 4 20 46 5 1 1 48 2 15 2 42 3 09 3 36 03 4 30 57 5 2 1 52 2 20 2 48 3 16 3 44 12 4 40 5 08 5 3 1 56 2 25 2 54 3 23 3 52 21 4 50 5 19 5 4 2 00 2 30 3 00 3 30 4 00 30 5 00 5 30 6 2 04 2 35 3 06 3 37 4 08 39 5 10 5 41 6 1 2 08 2 40 3 12 3 44 4 16 48 5 20 5 52 6 2 2 12 2 45 3 18 3 51 4 24 57 5 30 6 03 6 3 2 16 2 50 3 24 3 58 4 32 5 06 5 40 6 14 6 4 2 20 2 55 3 30 05 4 40 5 15 5 50 6 25 7 2 24 3 00 3 36 12 4 48 5 24 6 00 6 36 7 1 2 28 3 05 3 42 19 4 56 5 33 6 10 6 47 7 2 2 32 3 10 3 48 26 5 04 5 42 6 20 6 58 7 3 2 36 3 15 3 54 33 5 12 5 51 6 30 7 09 7 4 2 40 3 20 4 00 40 5 20 6 00 6 40 7 20 8 2 44 2 48 2 52 3 25 3 30 3 35 06 12 18 4 47 4 54 5 01 5 28 5 36 5 44 6 09 6 18 6 27 6 50 7 00 7 10 7 31 7 42 7 53 8 1 8 2 8 3 2 56 3 00 3 04 3 08 3 40 3 45 3 50 3 55 24 30 36 42 5 08 5 15 5 22 5 29 5 52 6 00 6 08 6 16 6 36 6 45 6 54 7 03 7 20 7 30 7 40 7 50 8 04 8 15 8 26 8 37 8 4 9 9 1 9 2 3 12 3 16 3 20 4 00 4 05 4 10 48 54 5 00 5 36 5 43 5 50 6 24 6 32 6 40 7 12 7 21 7 30 8 00 8 10 8 20 8 48 8 59 9 10 9 3 9 4 10 3 24 3 28 3 32 3 36 3 40 3 44 3 48 3 52 3 56 4 00 4 15 4 20 4 25 4 30 4 35 4 40 4 45 4 50 4 55 5 00 5 06 5 12 5 18 5 24 5 30 5 36 5 42 5 48 5 54 6 00 5 57 6 04 6 11 6 18 6 25 6 32 6 39 6 46 6 53 7 00 6 48 6 56 7 04 7 12 7 20 7 28 7 36 7 44 7 52 8 00 7 39 7 48 7 57 8 06 8 15 8 24 8 33 8 42 8 51 9 00 8 30 8 40 8 50 9 00 9 10 9 20 9 30 9 40 9 50 10 00 9 21 9 32 9 43 9 54 10 05 10 16 10 27 10 38 10 49 11 00 jrv^-^^. 10 1 10 2 10 3 10 4 11 11 1 11 2 11 3 11 4 12 s-^~*~ 3(5 146 ILLUSTRATED CATALOGUE OF TABLE. AZIMUTHS OF POLARIS, At the time of greatest elongation, from the year 1881 to 1900, and from latitude 30deg. to 49deg. north. COMPUTED BY W. J. LEWIS, C. E. year. L. 30 L. 31 L. 32 L. 33 iL. 34 L. 35 L. 36 L. 37 L. 38 L. 39 year. J. C. SALA, SAN FRANCISCO I 47 TABLES. IIOWIIIK lauies give me greaiebi eastern ana western Elongation of the North ) Star ( Polaris), in common clock time, for every third day in the year when the star L is visible. EASTERN ELONGATION. | f Day ) of Month April. May. June. July. August. September.^ h . m in h min . min. h, min. h min h min 1 6 39 A.M 4 41 A.M 2 39 A.M 41 A.M 10 35 P.M 8 32 P.M 4 6 27 " 4 29 " 2 28 " 30 " 10 23 " 8 20 " 7 6 15 " 4 17 " 2 16 " 18 10 12 " 8 08 " 10 6 03 " 4 05 " 2 04 " 06 10 00 " 7 56 " 13 5 52 " 3 53 " 1 52 11 49 1 M 9 48 ' 7 45 " 16 5 40 3 41 1 40 11 37 9 36 " 7 33 " ( 19 5 28 3 30 1 28 11 25 9 24 " 7 21 " 22 5 16 ' 3 18 1 17 " 11 14 9 12 " 7 09 " 25 5 04 3 06 1 05 " 11 02 9 01 " 6 57 " 28 4 52 ' 2 54 53 " 10 50 8 49 " 6 46 " 31 2 42 10 38 8 37 " WESTERN ELONGATION. Day of October. November. December. January. February. March. Month h min h. min. h. min. h. min. h- min. h. min. 1 6 27 A". M 4 24 A. M 2 26 A.M 27 A.M 10 21 P.M 8 31 P,M 4 6 15 " 4 13 2 14 " 15 " 10 09 " 8 18 " 7 6 03 " 4 01 2 02 " 12 00 P.M 9 58 " 8 06 " 10 5 51 " 3 49 1 51 " 11 48 " 9 46 " 7 55 " 13 5 39 " 3 37 1 39 " 11 36 " 9 34 " 7 44 " 16 5 27 " 3 25 1 27 " 11 24 " 9 22 " 7 32 " 19 5 16 " 3 13 1 16 " 11 12 9 10 " 7 20 " ( 22 5 04 " 3 02 1 04 " 11 01 ' 8 59 " 7 08 " ( 25 4 52 " 2 50 52 " 10 49 8 47 " 6 56 " ( 28 4 40 " 2 38 41 " 10 36 ' 8 35 " 644 " ( 31 4 28 " 30 " 10 25 6 33 " } An approximation to the true meridian m ght be ob- . tained by sighting on the Pole Star at the instant when ,-W-. ^ it is on the same vertical plane with Alioth. TheNorth \ Star is exactly in the true meridian 26 minutes lp,Jtoe after it has been in the same vertical plane with Alioth, ( and may be sighted after that i nterval of time with per- ) feet accuracy. ) On the first day of January, 1882, the right ascen- sion of Polaris will be: In. 15m. 30sec., and of Alioth ) 13 h 42m t3sec. When therefore Polaris arrives at the meridian, Alioth will be 27 m. 23 sec. to the East. ( Hence when Alioth is directly under Polaris, or in ( the same vertical plane, the pole is to the West of this ( plumb line, ranging from iOmin. 38 sec. in arc in lat. 30deg. north to 14 min. 2sec. in lat. 49 deg. north. * . The azimuth for every second degree of latitude is -JL j shown in the following table: / -. Lat. 28 10 27 36 11 23 44 III. 0. / %t I 12 48 ,-' > '> 10 38 38 11 41 46 13 15 -,. ..,-" *, / \ 32 10 51 40 12 01 480 13 46 -' "'*" '# > 340 11 06 42 12 23 49 14 02 ^ ft 148 ILLUSTRATED CATALOGUE OF EXPLANATORY NOTES. EXPLANATION OF THE TABLES. chains. As CO min. : 26 min. 6 sec. : : 5517.205 chains. 24.00 the distance required. Tables I and 1 1. Table I gives the length of a degree of latitude, in chains, for every minute of latitude between 29 and 49 degrees, calculated by the Formula Dm 5523.8724 27.7425 cos 2 I + .0592 cos 4 I, in which Dm represents a degree of the meridian, and I, the middle latitude. Table II gives the length c^a degree of longitude, in chains, for every minute of latitude between 29 and 49 degrees, calculated by the formula Dp = 5&S7.7439 cos I -4.6337 cos 3 I + 0058 cos 5 I, in which Dp represents a degree of the parallel and I, the latitude. These tables are useful for converting linear into angular, and angular into linear meusure, as well as for determining the convergencies and divergencies of the nit ridians, on the spheroidal surface of the earth. PROBLEMS AND EXAMPLES. 1. Given thf latitudes of any two places on the same meridian, to Jind the distance between them. RCLE. Find, from Table I, the length of a degree of the meridian at each latitude, and take half their sum for the mean length of a degree. Then say, as 60 minutes is to the difference of latitude, so is the mean length of a degree to the distance required. / The latitude of the Monte Diablo Base Line, is 37 deg. 52 min. 47 sec., and that ( of the 1st, Standard North, 38 deg. 18 min, 53 sec. ; what is the meridional distance ( between them? ( 2. Given the distance between any two places on the same meridian , and the latitude of one of them to find their difference of latitude. RULE. Find, from Table I, the length of a degree of the meridian, in the given latitude, and also in that differing from it, by the meridional distance, converted into an arc at the rate of 52 seconds per mile, and take half their sum for the mean length of a degree. Then say, as the mean length of a degree J is to the meridional distance, so is 60 minutes to the difference of latitude re- ( quired. < The latitude of the Monte Diablo Base Line, is 37 deg. 52 min. 47 sec.; what is < the latitde of the 1st Standard North, the meridional distance being 30 miles ? < chains. chains. As 5517.205 : 2400 : : 60 min. : 26 min. 6 sec, the difference of latitude required. ( 3. Given the longitudes of any two places, on the same parallel, in a ( given latitude, to find the distance between them. RULE. Find, from Table II, the length of a degree of longitude in the given latitude: and say, as 60 minutes is to the difference of longitude, so is the length of the degree of longitude to the distance required. The longitude of Monte Diablo Meridian is 121 deg. 54 min. 49 sec., and that ( of Range 1 East, 121 deg. 21 min. 53 sec. ; what is the distance between them, on ) t lie Base Line, in latitude 37 deg. 52 miu. 47 sec.? chains chains As 60 min. : 32 min. 56 sec. : : 4372.51 : 2400, the distance required. ) J. C. SALA, SAN FRANCISCO 149 EXPLANATORY NOTES. ^ 4. (riven the distance between any two places on in a given latitude, to find their difference o ) RULE. Find from Table II, the length of degree of longitude in the given ? latitude ; and say, as the length of the degree of longitude is to the given distance, so is 60 minutes to the difference of longitude. The longitude of the Monte Diablo Meridian, is 121 deg 54 min. 49 sec : what is ) the difference of longitude to Range 5 East, the distance' on the Base 'Line, in \ latitude 37 deg. 52 min . 47 sec., being 30 miles? ) chains, chains. As 4373 51: 2400: 60 min.: 32 min. 56 sec, the difference of longitude required. ( 5. (riven the distance between two meridians, on any parallel, in a given latitude, to find the convergency of the meridians for any distance north of that parallel. UULE. Find the length of a degree of longitude, at each latitude, by the fore- going rules; and say, as the greater of the two lengths is to their difference, so is ' the given distance to the convergency required. ' The distance between Ranges 1 and 2 on the 1st Standard South, is 6 miles, f what is the convergency of the two range lines at the 2d Standard North, the me. ^ riiiional distance being 30 miles? ? chains, chains, chains, chains. .' As 4346. 66 : 26.07 : : 480 : 2.88, the convergency required. ; i>. (riven the distance between two meridians, on any parallel in a given latitude, to find the divergency of the meridians for any distance south of that parallel. RULE, Find the length of a degree of longitude, at. each latitude, by the tore- \ going rules ; and say, as the less of the two lengths is to their difference, so is ) the given distance to the divergency required. <" The distance between Ranges 1 and 2, on the 1st Standard South, is 6 miles ; ) what is the divergency of the two range lines at the 2d Standard South, the meridional distance being 24 miles? chains, chains, chains, chains. As 4393.00 : 20.34 : : 480 : 2.22, the divergency required. Table III. This table gives the divergency of the Parallel of Latitude from the Prime Vertical,* or perpendicular to the meridian, on the spheroidal surface of the earth- { at every second degree of latitude, from 23 to 43 degrees, for any number of / miles from 1 to 36; and is useful in running a parallel of latitude by fore and V back sighting. ( The length of a degree of the Prime Vertical may be calculated by the Formula , ) Dv = 5551 6748-18 6536 cos 2J +.0940 cos 4 I ; in which Dv represents a degree of \ t the Prime Vertical, in chains, and I the latitude. C EXAMPLE. If a line commenced on the parallel of 37 degrees north latitude, be ^tended east or west, 27* miles, by fore and back sighting, what distance will its terminus be south of that parallel ? chains. The table gives for 27 miles in latitude 37 deg. . . 5.52 The mean o f which is ..................... 5.73 the distance required. ; 150 ILLUSTRATED CATALOGUE OF T A B L E . I Length of a Degree of Latitude. / 290 30 310 320 330 340 350 360 37 380 / ' chains. chains. chains. chains. chains. chains. chains. chains. chains. chains 509-15 5509-97 5510-82 5511-67 5512-55 5513-44 5514-34 5515-25 5516-lf 5517-11 ) 1 09-16 09-99 10-83 11-69 12-56 13-45 14-35 15-27 16-19 17-13 1 ,' 2 09-17 10-00 10-84 11-70 12-58 13-47 14-37 15-28 16-21 17-14 2 3 09-19 10-01 10-86 11-72 12-59 13-48 14-38 15-30 16-22 17-M 3? 4 09-20 10-03 10-87 11-73 12-61 13-50 14-40 15-31 16-24 17-17 *( 5 09-21 10-04 10-89 11-75 12-62 13-51 14-42 15-33 16-25 17-19 5? 6 09-23 10-06 10-90 11-76 12-64 13-53 14-43 15-34 16-27 17-20 6> 7 09-24 10-07 10-91 11-78 12-65 13-54 14-45 15-36 16-28 17-22 7) H 09-25 10-08 10-93 11-79 12-67 13-56 14-46 15-38 16-30 17-23 8) g 09-27 10-10 10-94 11-81 12-68 13-57 14-48 15-39 16-32 17-25 9 10 09-28 10-11 10-96 11-82 12-70 13-59 14-49 15-41 16-33 17-27 10 11 09-30 10-13 10-97 11-83 12-71 13-60 14-51 15-42 16-35 17-28J11 12 09-31 10-14 10-99 11-85 12-73 13-62 14-52 15-44 16-36 17-3012 13 09-32 10-15 11-00 11-86 12-74 13-63 14-54 15-45 16-38 17-3113 14 09-34 10-17 11-01 11-88 12-76 13-65 14-55 15-47 16-39 17-3314 15 09-35 10-18 11-03 11-89 12-77 13-66 14-57 15-48 16-41 17-3415 16 09-36 10-19 11-04 11-91 12-79 13-68 14-58 15-50 16-42 17-3616 17 09-38 10-21 11-06 11-92 12-80 13-69 14-60 15-51 16-44 17-3817 18 09-39 10-22 11-07 11-94 12-81 13-71 14-61 15-53 16-46 17-3918 19 09-41 10-24 11-09 11-95 12-83 13-72 14-63 15-54 16-47 17-4119 20 09-42 10-25 11-10 11-96 12-84 13-74 14-64 15-56 16-49 17-4220 21 09-43 10-26 11-11 11-98 12-86 13-75 14-66 15-57 16-50 17-4421 22 09-45 10-28 11-13 11-99 12-87 13-77 14-67 15-59 16-52 17-4522 23 09-46 10-29 11-14 12-01 12-89 13-78 14-69 15-61 16-53 17-47 23 24 09-47 10-31 n-ie 12-02 12-90 13-80 14-70 15-62 16-55 17-49 24 25 09-49 10-32 11-17 12-04 12-92 13-81 14-72 15-64 16-56 17-50 25 26 09-50 10-33 11-19 12-05 12-93 13-83 14-73 15-65 16-58 17-52 20 27 09-51 10-35 11-20 12-07 12-95 13-84 14-75 15-67 16-60 17-53 27 28 09-53 10-36 11-21 12-08 12-96 13-86 14-76 15-68 16-61 17-55 28 29 09-54 10-38 11-23 12-10 12-98 13-87 14-78 15-70 16-63 17-56 29 30 09-56 10-39 11-24 12-11 12-99 13-89 14-79 15-71 16-64 17-58 30 31 09-57 10-41 11-26 12-12 13-01 13-90 14-81 15-73 16-66 17-60 31 32 09-58 10-42 11-27 12-14 13-02 13-92 14-82 15-74 16-67 17-61 32 33 09-60 10-44 11-29 12-15 13-04 13-93 14-84 15-76 16-69 17-63 33 34 09-61 10-45 11-30 12-17 13-05 13-95 14-86 15-77 16-70 17-64 34 35 09-63 10-46 11-31 12-18 13-07 13-96 14-87 15-79 16-72 17-66 35 3f 09-64 10-48 11-33 12-20 13-08 13-98 14-89 15-81 16-74 17-67 36$ 37 09-65 10-49 11-34 12-21 13-10 13-99 14-90 15-82 16-75 17-69 " 38 09-67 10-50 11-36 12-22 13-11 14-01 14-92 15-84 16-77 17-71 38 < 39 09-68 10-52 11-37 12-24 13-13 14-02 14-93 15-85 16-78 17-7,2 39 r 40 09-69 10-53 11-39 12-26 13-14 14-04 14-95 15-87 If/80 17-74 40 41 09-71 10-55 11-40 12-27 13-16 14-05 14-96 15-88 16-81 17-75 41? 42 09-72 10-56 11-42 12-29 13-17 14-07 14-98 15-90 16-83 17-77 42 (' 43 09-74 10-57 11-43 12-30 13-18 14-08 14-99 15-91 16-84 17-78 43) 44 09-75 10-59 11-44 12-31 13-20 14-10 15-01 15-93 16-86 17-80 44 ,> 45 09-76 10-60 11-46 12-33 13-21 14-H 15-02 15-94 16-88 17-82 45) 4f 09-78 10-62 11-47 12-34 13-23 14-13 15-04 15-96 16-89 17-833 4<;', 47 09-79 10-63 11-49 12-36 13-24 14-14 15-05 15-98 ic-yi 17-85 47 ' 48 09-80 10-65 11-50 12-37 13-26 14-16 15-07 15-99 16-92 17-86 48 49 09-82 10-66 11-52 12-39 13-27 14-17 15-08 16-01 16-94 17-88 49' 50 09-83 10-67 11-53 12-40 13-29 14-19 15-10 16-02 16-95 17-89 50 51 09-85 10-69 11-54 12-42 13-30 14-20 15-11 16-04 16-97 17-91 MS 52 09-86 10-70 11-56 12-43 13-32 14-22 15-13 16-05 16-98 17-93 V2 53 09-87 10-72 11-57 12-45 13-33 14-23 15-15 16-07 17-00 17-94 ">3 54 09-89 10-73 11-59 12-46 13-35 14-25 15-16 16-08 17-02 17-96 54 r>r 09-90 10-74 11-60 12-48 13-36 14-26 15-18 16-10 17-03 17-97 r >r> 56 09-92 10-76 11-62 12-49 13-38 14-28 15-19 16-11 17-05 17-.)'.) 56 57 09-93 10-77 11-63 12-51 13-39 14-29 15-21 16-13 17-06 18-00 57 58 09-94 10-79 11-65 12-52 13-41 14-31 15-22 16-15 17-08 18-02 58 59 09-96 10-80 11-66 12-53 13-42 14-32 15-24 16-16 17-09 18-04 59 6C 09-97 10-82 11-67 12-55 13-44 14-34 15-25 16-18 17-H 18-05 to J. C. SAI 18-45 19-40 20-30 21-32 , 18-4f. 19-41 20-37 21-33 18-48 19-43 20-39 21-35 ^ IH'4'.I 19-45 20-40 21-36 18-51 19-46 20-42 21-38 ) 18-53 19-48 20-44 21-40 L 18-54 19-49 20-45 21-41 I 18-5(1 19-51 20-47 21-43 J 18-57 19-53 20-48 21-45 I 18-5'J 19-5 20-50 21-46 '> 18-00 19-5 20-52 21-48 ') 18-62 19-5 20-53 21-48 1 18-64 19-59 20-55 21-51 3 18-65 19-6 20-56 21-53 3 18-67 19-6 20-58 21-54 3 18-68 UN; 20-60 21-56 1 18-70 19-6 20-6 21 -51 2 18-72 19-6 20-63 21-M 3 18-73 19-6 20-64 21-61 4 18-75 19-7 20-6 21-65 5 18-7f 19-7 20-6 21-64 6 18-78 19-7 20-69 21 -6 7 18-7r 19-7 20-7 21 -6 r 8 18-81 19-7 20-7 21-61 9 18-8J 19-7 20-7 21-7f 18-84 19-8 20-7 21-75 1 18-8f 19-8 20-7 21-74 2 18-8 r 19-8 20-7 21-7? 3 18-81 19-8 20-8 21-7 r 4 18-9] 19-8 20-8 21-7* 5 18-95 19-8 20-84 21-8( 6 18-94 19-8 20-85 21 -85 7 18-9J 19-9 20-87 21 -K 8 18-9 r 19-9 20-88 21-8J 9 18-9J 19-9 20-9C 21-8C 19-(X 19-9 20-95 21-8J 24-59 25-56 26'6_ _. _ 24-61 25-57 26-54 27-50 4S 24-62 25-59 26-56 27-52 BC 24-64 25-61 26-5 152 ILLUSTRATED CATALOGUE OP . T A B L E. II . Length of a Degree of Longitude. >r ^X^N^- 29 ^s^-s-<-s 30 V^-N^^-'- 31 i^-^~^r~ 32 ^S^S^s^. 330 ^^^~S-^ 340 /~^^*^^ 35 S^S^r* 36 ^v_^v~/-v 37 ^**^-*~j-* 38 **_/~ / 1 chains. chains. chsiins. chains. chains chains. chains. chains. chains. chains. I 843-17 795-82 747-01 4696-75 4645-06 4591-96 4537-45 4481-56 4424-29 4365-68 1) I 1 42-40 95-02 46-19 95-90 44-19 91-06 36-53 80-61 23-33 64-69 1 1 41-62 94-22 45-36 95-05 43-32 90-16 35-61 79-67 22-36 63-70 2 3 40-84 93-42 44-53 94-20 42-44 89-26 34-69 78-73 21-40 62'72 3 4 40-06 92-61 43-71 93-35 41-57 88-37 33-77 77-78 20-43 61-73 4 5 39-28 91-81 42-88 92-50 40-69 87-47 32-84 76-84 19-46 60-74 5 6 38-50 91-01 42-05 91-65 39-82 86-57 31-92 75-89 18-49 59-75 6 7 37-72 90*20 41-22 90-80 38-94 85-67 31-00 74-95 17-53 58-76 7 8 36-94 89-40 40-39 89-94 38-06 84-77 30-08 74-00 16-56 57-77 8 9 36-16 88-59 39-56 89-09 37-19 83-87 29-15 73-05 15-59 56-77 g 10 35-38 87-79 38-73 88-24 36-31 82-97 28-23 72-11 14-62 55-78 10 Ul 34-60 86-98 37-90 87-38 35-43 82-07 27-30 71-16 13-65 54-79 11 '12 33-82 86-18 37-07 86-53 34-55 81-17 26-38 70-21 12-68 53-80 12 i:( 33-04 85-37 36-24 85-67 33-68 80-26 25-46 69-26 11-71 52-81 13 14 32-26 84-56 35-41 84-82 32-80 79-36 24-53 68-32 10-74 51-81 14 15 31-47 83-76 34-58 83-96 31-92 78-46 23-60 67-37 09-77 50-82 15 H 30-69 82-95 33-75 83-11 31-04 77-56 22-68 66-42 08-80 49-83 i<; 17 29'91 82-14 32-92 82-25 30'lfe 76-65 21-75 65-47 07-82 48-83 17 18 29-12 81-33 32-08 81-40 29-28 75-75 20-83 64-52 06-85 47-84 18 1! 28-34 80-52 31-25 80-54 28-40 74-85 19-90 63-57 05-88 46-84 19 2! 27-55 79-71 30-42 79-68 27-52 73-94 18-97 62-62 04-91 45-85 20 \21 26-77 78-90 29-58 78-82 26-64 73-04 18-04 61-67 03-93 44-85 21 '22 25-98 78-09 28-75 77-97 25-75 72-13 17-11 60-72 02-96 43-85 22 23 25-20 77-28 27-92 77-11 24-87 71-23 16-19 59-77 01-98 42-86 23 24 24-41 76-47 27-08 76-25 23-99 70-32 15-26 58-81 01-01 41-86 24 26 23-62 75-66 26-25 75-39 23-11 69-41 14-33 57-86 00-04 40-86 25 2( 22-83 74-85 25-41 74-53 22-22 68-51 13-40 56-91 4399-06 39-87 26 27 22-05 74-04 24-57 73-67 21-34 67-60 12-47 55-96 98-08 38-87 27 28 21-26 73-22 23-74 72-81 20-45 66-69 11-54 55-00 97-11 37-87 28 21 20-47 72-41 22-90 71'95 19-57 65-78 10-61 54-05 96-13 36-87 2!) 30 19-68 71-60 22-06 71-09 18-69 64-88 09-67 53-09 95-16 35-87 30 ( *1 18-89 70-78 21-22 70-22 17-80 63-97 08-74 52-14 94-18 34-87 31 32 1810 69-97 20-39 69-36 16-91 63-Of 07-81 51-19 93-20 33-87 32 ; w 17-31 69-16 19-55 68'50 16-03 62-15 06-88 50-23 92-22 32-87 .33 34 16-52 68-34 18-71 67-64 15-14 61-24 05-94 49-27 91-25 31-87 34 ar 15-73 67-53 17-87 66'77 14-26 60-33 05-01 48-32 90-27 30-87 35 r )3( 14-94 66-71 17-03 65'91 13-37 59-42 04-08 47-36 89-29 29-87 36 (87 14-15 65-89 16-19 65'05 12-4b 58-51 03-14 46-41 88-31 28-87 137 (38 13-35 65-08 15-35 6418 11-59 57-60 02-21 45-45 87-33 27-87 38 ' 3! 12-56 64-26 14-51 63-32 10-70 56-68 01-28 44-49 86-35 26-87 39 4( 11-77 63-44 13-67 62'45 09-81 55-77 00-34 43-53 85-37 25-86 40 41 10-98 62-52 12-82 61*81 08-93 54-8f 4499-40 42-57 84-39 24-86 41 42 10-18 61-81 11-98 6072 08-04 53-95 98-47 41-62 83-41 23-86 42 )48 09-39 60-99 11-14 59'85 07-15 53-03 97-53 40-66 82-42 22-85 43 '44 08-59 60-17 10-30 58'99 06-26 52-12 96-59 39-70 81-44 21-85 44 )45 07-80 59-3, 09-45 58-12 05-36 51-21 95-66 38-74 80-46 20-85 45 4( 07-00 58-53 08-61 57'25 04-47 50-29 94-72 37-78 79-48 19-84 46 < 06-21 57-7 07-76 56'38 03-58 49-38 93-78 36-82 78-49 18-84 47 48 05-4 56-89 06-92 55'51 02-69 48-46 92-84 35-86 77-51 17-83 48 (48 04-6 56-07 06-07 54'65 01-80 47-55 91-91 34-89 76-53 16-82 49 5( 03-8 55-25 OS'23 53'78 00-90 46-61 90-97 33-93 75-54 15-82 50 51 03-0 54-43 04-3 52'91 03-01 45-71 90-03 32-97 74-56 14-81 51 /52 02-2 53-6 03'54 52'04 4599-12 44-80 89-09 32-01 73-57 13-80 ->2 69 01-4 52-7 02-69 5117 98-22 43-88 88-15 31-04 72-59 12-80 53 M 00-6 51-9 01'84 50-30 97-33 42-iH 87-21 30-08 71-60 11-79 54 5 4799-8 61-1 01-00 49-42 96-44 42-04 86-27 29-12 70-62 10-78 56 <<> 99-021 50-3 00-15 48' 55 95-54 41-13 85-32 28-15 69-63 09-77 -><; 6 98-22 49-49 4699-30 47 '68 94-64 40-21 84-38 2719 68-64 08-76 57 )5 97-42 48-6 98-45 46-81 93-75 3H-2J 83-44 26-22 67<66 07-75 58 ) 5 96-62 47-8 97-60 45-94 92-85 38-37 82-50 25-26 66-67 06-74 59 jfl 95-821 47-0 96-75 45-06 91Tf 37- IF 81 -5r 21-29 65-08 05-73 60 J. C. SAL A, SAN FRANCISCO T ABLE.TF- Length of a Degree of Longitude. >, 39 400 410 42^ 430 440 450 460 470 480 ' ! chains. chains. ;ha'.ns. lair.s. lains lains. cluh.s. wins. bains. aains. > 4305.73 44-47 4 181-91 18-06 052-96 986-62! 5919-05 850-28 780-33 709-22 1 04-72 43-44 80-85 1C-U9 51-87 85-50 17-91 49-12 79-15 08-03 1 2 03-71 42-41 79-80 15-91 50-77 84-38 16-78 47-97 77-98 06-83 2 i 3 02-70 41-37 78-75 14-84 49-67 83-27 15-64 46-81 76-80 05-63 3 4 01-69 40-34 7769 13-76 48-58 82-15 14-50 45-65 75-63 04-44 4 5 00-68 39-31 7G-64 12-69 47-48 81-03 13-36 44-50 74-45 03-24 5 i 4299-67 38-27 75-58 11-61 46-38 79-91 12-23 43-34 73-27 02-05 6 7 98-65 37-24 74-52 10-53 45-28 78-79 11-09 42-18 72-09 00-85 7 8| 97-64 36-20 73-47 09-46 44-19 77-68 09-95 41-02 70-92 699-65 8 9 96-63 35-17 72-41 08-38 43-09 76-56 08-81 39-86 69-74 98-46 9 10 95-61 34-13 71-36 07-30 41-99 75-44 07-67 38-70 68-56 97-2610 11 94-60 33-10 70-30 06-22 40-89 74-32 06-53 37-54 67-38 96-0611 12 93-59 32-06 69-24 05-14 39-79 73-20 05-39 36-38 66-20 94-8612 19 92-57 31-02 68-18 04-07 38-69 72-08 04-25 35-22 65-02 93-6613 14 91-56 29-99 67-12 02-99 37-59 70-96 03-11 34-06 63-84 92-4614 16 90-54 28-95 66-07 01-91 36-49 69-84 01-97 32-90 62-66 91-2615 1C 89-52 27-91 65-01 00-83 35-39 68-72 00-83 31-74 61-48 90-06 16 17 88-51 26-87 63-95 099-75 34-29 67-59 899-69 30-58 60-3 88-8617 18 87-49 25-84 62-89 98-67 33-19 66-47 98-54 29-42 59-1 87-6618 1] 86-48 24-80 61-83 97-58 32-09 65-35 97-40 28-26 57-9 86-4619 21 85-46 23-76 60-77 96-50 30-98 64-23 96-26 27-09 56-7 85-2620 21 84-44 22-72 59-71 95-42 29-88 63-11 95-12 25-93 55-5 84-0621 21 83-42 21-68 58-65 94-34 28-78 61-98 93-97 24-77 54-3 82-8622 21 82-40 20-64 57-58 93-26 27-67 60-86 92-83 23-60 53-2 81-6623 24 81-39 19-60 56-52 92-17 26-57 59-73 91-68 22-44 52-0 80-4624 2.' 80-37 18-56 55-46 91-09 25-47 58-61 90-54 21-28 50-8 79-2525 2( 79-35 17-52 54-40 90-01 24-36 57-49 89-4 20-11 49-6 78-0526 2" 78-33 16-48 53-44 88-92 23-26 56-36 88-2 18-9 48-4 76-8527 77-31 15-43 52-27 87-84 22-15 55-24 87-1 17-7 47-2 75-64 28 2'. 76-29 14-39 51-21 86-7 21-0 54-11 85-9 16-6 46-1 74-44 29 81 75-27 13-35 50-1 85-6 19-94 52-98 84-8 15-4 44-9 73-2430 s: 74-24 12-31 49-0 84-5 18-8 51-86 83-6 14-2 43-7 72-03 31 3- 73-22 11-26 48-05 83-5 17-7 50-7 82-5 13-1 42-5 70-83 32 72-2 10-2 46-9 82-4 16-6 49-6 81-3 11-9 41-3 69-6233 ;{- 71-1 09-1 45-8 81-3 15-5 48-4 80-2 10-7 40-1 68-4234 :i 70-1 08-1 44-8 80-2 14-4 47-3 79-0 09-6 38-9 67-21 35 1 :{ 69-1 07-0 43-7 79-1 13-3 46-2 77-9 08-4 37-8 66-01 30 a 68-1 06-0 42-6 78-0 12-1 45-0 76-7 07-2 36-6 64-8037 67-0 05-0 41-6J 76-9 11-0 43-9 75-6 06-1 35-4 63-5938 N is 66-0 03-9 40-5 75-8 09-9 42-8 74-4 04-9 34-2 62-39 39 4 65-04 02-9 39-4 74-8 08-8 41-7 73-3 03-7 33-0 611840 64-0 01-8 33-4 73-7 07-7 40-5 72-1 02-6 31-8 59-97 41 62-9 00-8 37-3 72-6 06-6 39-4 71-0 01-4 30-6 58-76 42 < 61-9 4199-7 36-26 71-5 05-5 38-3 69-8 00-2 29-4 57-56 43 ( 60-9 59-9 98-7 97-6 35-2 34-1 70-4 69-3 04-4 03-C 37-1 36-0 68-7 67-5 3799-1 97-9 28-3 27-1 56-35 44 55-1445 58.8 96-6 35-0 68-2 02-2 34-9 66-4 96-7 25-9 53-93 46 57-8 56-8 55-8 KAS 95-5 94-5 93-4 32-0 30-9 29-8 28"' 67-1 66-0 64-9 63*5 01-1 3999-9 98-8 97-7 33-7 32-6 31-5 30-3 65-2 64-1 62-9 61-8 95-5 94-4 93-2 92-0 24-7 23-5 22-3 21-1 52-7247 51-51 48 50-3049 49-0950 '. Oi I 53-7 91-J 27-7 62-8 96-6 29-2 60-6 90-9 19-9 47-8851 1 I; 52-7 51-6 49-f G 48-5 >7l 47-r >8| 40- 59 4.Vj 501 44-4 90-3 89-2 88-2 87-1 86-1 85-0 84-0 82-9 7 81-9 26-6 25-5 24-5 23-4 22-3 21-2 20- 19. 18- 61-7 60-6 59-5 58-4 57-3 56-2 55-1 54-0 52-9 95-5 94-4 93-3 92-1 91-0 89-9 88-8 87-7 86-6 28-1 26-9 25-8 24-7 23-5 22-4 21-3 20-1 19-0 59-5 68-3 67-2 66-0 54-9 53-7 52-5 51-4 50-2 89-7 88-5 87-3 86-2 85-0 83-8 82-6 81-5 80-3 18-7 17-5 16-3 15-1 14-0 12-8 11-6 10-4 09-2 46*67 52 ( 45-46 53 44-2554 43-03 55 41-8256 40-61 5T 39-4058 38-1859 30-9 60, ^^/-^-"W-WN ILLUSTRATED CATALOGUE OP TABLE HI. i DIVERGENCY OF THE PARALLEL OF LATITUDE AND THE < PRIME VERTICAL. i Dist 280 300 320 340 1 360 380 40 42 o 440 460 480 Dist mile chns chns chns chns ! chns chns chns chns chns chns chi mile 1 0.01 0.01 0.01 0.01 : C .01 0.01 0. )1 0.01 0.01 0.01 0. n' 1 2 0.02 0.02 0.03 0.03 i 0.03 0.03 0.03 0.04 0.04 0.04 0.04 2 3 0.05 0.05 0.06 0.06 : C .07 0.07 0. 08 0.08 0.09 0.09 0.] o 3 4 0.09 0.09 0.10 0.11 1 c .12 0.13 0. 13 0.14 0.16 0.17 0. 8 4 5 0.13 0.14 0.16 0.17 : 0.18 0.20 0.21 0.23 0-24 0.26 0.28 5 6 0.19 0.21 0.23 0.24 i c .20 0.28 0. 30 0.33 0.35 0.37 OJ. n 6 7 0.26 0.28 0.31 0.33 i 0.36 O.C8 0.41 0.44 0.48 0.51 0.55 7 ( 8 0.34 0.37 0.40 0.43 i C 47 0.50 0. 54 0.58 0.62 0.67 O. f i 8 ( 9 0.43 0.47 0.51 0-55 i 0.59 0.64 0.68 0.73 0.79 0.84 0.90 9 10 0.53 0.58 0.63 0.68 i .73 0.78 0. 44 0.90 0.97 1.04 i.: 1 101 11 0.65 0.70 0.76 0.82 : .88 0.95 1. )2 1.09 1.17 1.26 i.e. -^ 11 12 0.77 0.83 0.90 0.97 : 1.05 1.13 1.21 1.30 1.40 1.50 1.61 12 13 090 0.98 1.06 1.14 i 1 .23 1-33 1. 42 1.53 1.64 1.76 l.l R 13 14 1.05 1.14 1.23 1.33 i 1.43 1.54 1.65 1.77 1.90 2.04 2.19 14 15 1.20 1.30 1.41 1.52 1 .04 1.76 1. )0 2.03 2.18 2.34 2. 1 15 16 1.36 1.48 1.60 1.73 i 1.87 2.01 2.16 2.32 2.48 2.66 2.85 16 17 1.54 1.67 1.81 1.96 i 2 .11 2.27 2. 44 2.fil 2.80 3.00 3.2 9 17 18 1.73 1.88 2.03 2.19 i 2.36 2.54 2.73 2.93 3.14 3.37 3.61 18 ( 19 1.92 2.09 2.26 2.44 i 2 .03 2.83 3. J4 3.26 3.50 3.75 4.0 a 19 (. 20 2.13 2.32 2.51 2.71 : 2.92 3-14 3.37 3.02 3.88 4.16 4.46 20 ( 21 2.35 2.55 2.76 2.98 ! 3 .22 3.46 3. "2 3.99 4.28 4.59 4.9 2 21 ? 22 2.58 2.80 3.03 3.28 ! 3 .53 3-80 4. J8 4.38 4.69 5.03 5.4 n 22 r ) 23 2.82 3.06 3.32 3.58 3.86 4.15 4.46 4.78 5.13 5.50 5^90 Am ( 23 f / 24 3.07 3.34 3.61 3-90 4-20 4.52 4.85 5.21 5.59 5.99 6.42 24 ; 25 3.33 3.62 3.92 4.23 i 4 .50 4.90 5. 11 5.65 6.06 6.50 6.9 7 25 26 3.60 3.91 4.24 4.57 4.93 5.30 5.70 6.11 6.56 7.03 7.54 26 > ) 27 3-89 4.22 4.57 4.93 5 32 5.72 6. 14 6.59 7.07 7.58 8.1 a 27 ' ) 28 4.18 4.54 4.91 5-31 5.72 6.15 6.61 7.09 7.60 8.15 8.7-1 28 > S 29 4.48 4.87 5.27 5.69 6 13 6.60 )9 7.61 8.16 8.74 9.3 8 29 > < 30 4.80 5.21 5.64 6.09 6 50 7.06 7. 38 8.14 8.73 9.36 10.0 A 30 ) 31 5.12 5.57 6.02 6.50 7.01 7.54 8.10 8.69 9.32 9.99 10.79 31 ) 32 5.46 5.93 6.42 6.93 7 47 8.03 8L< Y3 9.26 9.93 L0.65 11.4 9 32 S 33 5.81 6.31 6.83 7.37 7.94' 8.54 9.18 9.85 10.56 L1.32 12.14 33 34 6.16 6.69 7.25 7.82 8 43 9.07 9.' '4 10.45 11.21 L2.02 12.8 1 34 35 6.53 7.09 7.63 8.2D 8-D3 9.61 10.32 11.08 11.88 12.74 13.66 35 < 36 6.9J 7.51 8.12 8.77 9.45 10.16 10.92 11.72 12.57 13.47 14.45 36 i TABLE showing the Difference of Latitude and Departure in running 80 chains, at any course from 1 to 60 minutes. Min's Links . Miu' s Links. Min's Links. Min's Links. lin's I inks. A lin's Links. J> 1 2i 11 25 f 21 49 31 72} 41 95f 51 119 ) 2 4;: 12 28 22 51} 32 741 42 98 52 121} S 3 7' 13 30} 23 63f 33 77 43 100J 53 123| ( 4 9} 14 32f 24 56 34 79} 44 1028 54 126 5 Hf 15 35 1 >5 58} 35 81f 45 105 55 128* < 6 14 16 37} i 6 60| 36 84 46 107} 56 130f < 7 16} 17 39? 27 63 37 86} 47 109i 57 133 ( 8 18 42 1 8 65* 38 88 48 112 58 135| < 9 21 3 19 44} 29 67f 39 91 49 114} 59 137* ' 10 23} 26 46 30 70 40 93} 50 L16f 60 140 21 2.55 .048 43 5.21 .099 65 7.88 .149 > 22 2-67 .051 44 5.33 .101 66 8.00 .151 ) 156 ILLUSTRATED CATALOGUE OF MISCELLANEOUS. APPROXIMATE RULES CONVENIENT IN PRACTICE. I. FOR CORRECTING RANDOM LINKS.* 1. Given the error of latitude or departure, for any distance, to find the error of the course. RULE. Three-sevenths of the error of latitude or departure, per mile, in links, will be the error of the course, in minutes. EXAMPLE. What is the error of the course for an error of 210 links of latitude or departure, in C miles ? Here the error, per mile, is 35 links, three-sevenths of which is 15 minutes, the error required. 2. Given the error of the course, to find the corresponding error of latitude or departure Jor any distance. RULE Seven-thirds of the error of the course, in minutes, will be the error of latitude or departure, per mile, in links. EXAMPLE. What is the error of latitude or departure, in 6 miles, for an error of 15 minutes in the course? Here seven thirds of 15 is 35 links, the error per mile, or 210 links in 6 miles, the error required. II. FOR RUNNING A PARALLEL OF LATITUDE^ Given the distance run, east or west, on a great circle, to find the divergency from the parallel of latitude. ROLE Multiply the square of the distance in miles, by the natural tangent of the latitude, and the product wi-11 be the divergency, in links. EXAMPLE. After running 6 miles, east, or west, on the arc of a great circle, from latitude 38 degrees, what will be the meridional distance south of the parallel? Here we have .781x62 =~ 28 links, the divergency required TRIGONOMETRICAL SERIES A3' A 5 AT Sin A A + - + etc. 2.3 2.3.4.5 2.3.4.5.6.7 A2 A4 A6 Cos A 1 + + etc. 2 2.3.4 2.3.4 5.6 A3 2A5 17A? Tan A A + + + + etc 3 3.5 32.5.7 1 A A3 2A5 Cot A = etc. A 3 32.5 33 5.7 sin 3 A 3 sin 5 A 3.5 sin? A Arc A sin A + + + + etc. . 2.3 2.4.5 2.4.6.7 1 1 1 Arc A= tan A tan 3 A + tan^A tan?A + etc. 3 5 7 * This approximation is true to the nearest minute for all angles up to 3 deg. ; and to the nearest quarter of a degree for all angles up to 11 J degrees. t This approximation may be considered practically correct for any distance not exceeding 30 miles. J. C. SALA, SAN FRANCISCO sc K L L A NEO U S ) Rules for Solving all Cases of Plane Trigonometry. CASE 1. Given all the Angles and One Side, to find the other Side. ', Kri.i:. As sine of the angle opposite the given side, is to sine of the angle -He the required side, so is the given side lo the required side. CASE 2. ( Given two tii 0.55 13 2.63 21) 6.42 27 12.24 7 0.70 14 3.06 21 7.11 28 13.37 8 0.98 15 3.63 22 7.85 29 14.34 1.24 16 f 4.02 23 8.64 30 15.47 10 1,55 17 4.56 24 9.47 86 22.07 their difference, so is tangent of half sum of unknown angles, to tangent of half their difference. Add this half difference of the unknown angles to their half sum for the angle opposite the greater side, and subtract it from the half sum lor the angle opposite the less side. CASE 4. Given the Three Sides to find the Angles. RULE Upon the longest side let fall a perpendicular from the opposite angle. This perpendicular will divide the base into two segments and the triangle into two right-angled triangles ; then say, as the given base is to the sum of tire two other sides, so is the difference ot'those sides, to the difference of the segments of the base. To half the base add half the difference of the segments for the greater seg- ment, and subtract it from half the base for the less side; then proceed as in Case 2. < Rn.K *. Add together the arith. comp. of the logarithms of the two sidea, con- y taining the required angle, the log. of thehalf sum of the three sides and the log. of the difference of the half sum and the side opposite the required angle. The half sum of these four logarithms will be the logarithmic cosine of half the required angle. FOR FINDING THE DIAMETER OF A TREE. j^u K Annex a cipher to the number of links around the tree, and one fourth of the result will be the diameter, in inches. EXAMPLE. What is the diameter of a tree whose circumference is 16 links ? Here we have of 160 = 40 inches, the diameter required. ILLUSTRATED CATALOGUE OF T A B L E S. Position of the Principal Lines of the United States Surveys in the Stale of California. MONTE DIABLO Merid,, Mt.Diablo. Lat. 37 52" 47", Long. 121" 54' 49" W. ; PARALLEL. Latitude. Distance. Miles 30 60 90 120 150 180 210 240 270 284 24 48 72 96 12 ' 141 168 192 216 240 Longitude ' per Kange t Converg. Chains. ; 0.00 2.84 > 2.88 \ 2.93 <> 2.97 < 3.02 (' 2.06 ( 3.11 ( 3.16 } 3.21 - 1.48 } 2.25 > 2.22 S 2.19 ( 2.17 ( 2.14 ( 2.11 ( 2.09 ( 2.06 ( 2.03 k 2.00 ( ) Monte Diablo / // 37 52 47 / // | 35.2 6 37.5 j 6 3^.9 6 42.4 , 6 44.9 6 47-5 6 50.1 6 52.8 6 55.5 6 58.3 6 59.6 6 33-4 6 31.6 6 29.8 6 28.0 6 26.3 6 24-6 6 22.9 6 21.3 6 19.7 6 18.1 ) I Standard Kor:' .... S 11 38 18 53 38 44 58 ( 111 " " 39 11 4 ( V " " '.'". i 39 37 10 40 3 15 40 29 21 vis ?. ::: J> IX " " .... ' Oregon Boundary ) I Standard So-ith . . . ) 11 J 111 vi ' ^ ^ ::: 40 55 26 i 41 21 31 41 47 54 42 37 31 54 37 11 1 36 50 8 36 29 14 36 8 21 ! 35 47 28 VII VIII " " ... IX " "... X " " ... 35 26 35 ... 35 5 41 .... .34 44 48 .... 34 23 55 HUMBOLDT MERID., Mt. Pierce, Lat. 40 24' 56", Long.l2407' 03" \V. J PARALLEL. Latitude. Dio'.ance. Longitude per ilange. Converg. Mount Pierce O / r r .... 40 24 56 Miles. 30 60 90 109.32 24 r / // 6 49.6 6 52.3 6 55.0 6 57.9 6 5D.fi 6 47.5 Chains. { 0.00 r 3.15 / 3.20 ) 2.09 ) Diverg, / 2.48 ( 1 Standard North (* 11 " 40 51 1 .... 41 17 6 41 43 12 1 42 )l Standard South ... 40 4 4 ) SAN BERNARDINO Merid.. Mt.San Bern. I S < PARALLEL. Latitude. at. 34 07 Distance. ' 25", Long. 11656'W. ( / Longitude per Ilange. Converg. x 1 ; Mount San Bernardino . . . ) I Standard North 11 - " Ill " " >rv V " " VI o / // 34 7 25 34 33 32 34 59 39 35 25 46 35 51 53 i 36 18 36 44 6 Miles. 30 60 90 120 150 180 24 48 72 96 120 o / // 6 16.9 6 18.8 6 20.8 6 22.8 6 24.9 6 27.1 6 29.2 6 15.1 6 13.8 6 1?.! 6 10.9 6 9.5 Clriirs. ( 0.0(1 | 2.47 , 2.51 2.56 ; 2.60 ) 2.64 ) 2.68 S Diverg. ) 1.95 1.93 1.90 J.87 1.85 1 Standard South 11 " " HI " " x v - -: 33 46 31 33 25 38 33 4 34 32 43 50 32 22 56 J. C. SAL.A, SAN FRANCISCO TABLES 159 POSITION or THE PRINCIPAL LINES or THE UNITED STATES SUHVKYS IN THE STATE OF NEVADA. The principal Huso and Standard Parallels in this State are precisely the same as t hose of California. All the townships are numbered from the Monte Diablo meridian and bus, line. The Fourth Standard Parallel base line commences at the California and Nevada State lines, run by A. W. von Schmidt, at the line between Ranges 17 and IS, aud extends to the Utah boundary line in Range 70. There are four Guide Meridians, viz.: CABSON GUIDE MERIDIAN, running north from the Fourth Standard North, between Ranges 20 and 21 E. M. D. M. HUMBOLDT RIVER GUIDE MERIDIAN, running north from the Fourth Standard North, between ranges 35 and 36 E. M. D. M. REESE RIVER GUIDE MERIDIAN, running south from the Fourth Stan- dard North, between Ranges 42 and 43 E. M. D. M. P.UBY VALLEY GUIDE MERIDIAN, running N. and S. from the Fourth ' Standard Parallel North, between Ranges 55 and 56 of the Monte Diablo ' meridian. ( Position of the Principal Lines of the United States Surveys in ( UTAH $ Initial Point, Salt Lake Base and Meridian. (' Latitude, 40 46' 08" North; Longitude 111 53' 47" West. ( Surveys North of the Base Line. \ Parallel. Latitude. Distance Longitude, per Range. i* ConvergJ ^ Initial Point o / // 40 46 08 41 07 00 41 27 52 41 48 44 42 00 00 Miles. 24 48 72 84.95 o / // 6 51.8 6 53.9 6 56.1 6 58.4 6 59.6 Chains, / / 2.51 ' 2.54 2.58 1.40 I Standard North II " ' ( III " " ( Oregon Line Surveys South of the Base Line. Initial Point 40 46 08 40 20 03 39 53 57 39 27 51 39 01 46 38 35 40 38 09 34 37 43 28 37 17 22 37 00 00 Miles. 30 60 90 120 150 180 210 240 259.95 / ff 6 61.8 6 49.1 6 45.6 6 440 6 41.5 G 39.1 6 36.7 6 34.3 6 32.1 6 30.1 Chains I . 3.0& ' 3.C5 2.99 % 2.95 2.91 2.86 2.8JJ . 2.78 ' 2.31 I Standard South..., II III ' .. . IV " . V VI " . VII " ... VIII " .... ) Arizona Line COLORADO BASE LINE, Latitude of Initial Point, 33 deg. 51 mln. ;. . . .Longitude, 114 deg. 22 min. i Meridian runs north 12 miles to Lat. 34 deg. 1 min. 27 sec. Convergency, 0,97 chains. .' i6o ILLUSTRATED CATALOGUE OF T A JJ L E S ^ POSITION OF THE PRINCIPAL LINES OE THE U. S. Suiiv. iv ARIZONA 'PER. ) Initial Point, junct. of Salt & Gila rivers. Lat. 33 22" 57", Long. 112 15" 46" Surveys north, of Gila and Salt River Rise Line. ) Parallel. Latitude. Distance. Longitn de per K:mgc'. Converg. Chuins. 1.92 1.95 1.97 2.00 2.02 2.05 2.08 2.10 2.13 2.16 0.85 Chains. 2-37 2.33 ( 2.29 , 2.26 , ) ) Initial Point o / // 33 22 57 33 43 51 34 04 45 1 34 25 38 34 46 32 35 07 25 35 28 18 35 49 12 36 10 05 36 30 58 36 51 52 37 00 00 h of Gila and o / // 33 22 57 32 56 50 32 30 42 32 04 35 31 38 27 Allies. 24 48 72 96 120 144 168 192 210 240 249.35 Salt Rii Miles. 30 60 90 120 o / / / 6 13.6 6 15.1 o 6 K;.I; 6 18.2 6 19.8 6 21.4 6 2S.O 6 24.7 6 26.4 6 28.1 6 29.9 6 30.6 ~er Base Line. 1 Standard IS orth 11 " " . . . Ill " " . ^ :: :: VI \'ii via IX " "... X North Boundary . Surveys sout Initial Point I Standard South... 'II " " Ill IV " " Initial Point of Williametta MeridLn, WASHINGTON Base Line, Lat. 45 31 ' 13" North, Long. 122 CO' 2u" W. Parallel. Latitude. | Distance. Longitude per Range. ( Converg. ( Chuins. 00 < 2.96 ( 3.00 3.04 3.07 ) 3.11 ) 3.15 ) 3.19 ) 3.23 S 3.27 S 3.30 1 Initial Point o / // 45 31 13 45 52 04 46 12 55 46 33 46 4 '; ." :: :: ::: VI VII " " ; I Standard South..., } II 45 4(J 27 46 07 15 46 28 03 46 48 51 47 09 39 47 30 27 47 51 13 48 12 03 45 20 27 44 54 27 i Miles. 24 48 72 96 120 144 168 30 f-0 1 7 27.8 7 28.2 7 28.5 7 28.8 7 29.2 7 29.6 7 29.9 7 30.3 7 27.3 7 27.8 Chains. 00 / 3.01 ) 3.03 ( . 3.06 S 3.11 ( 3.15 3.19 3.22 ' Diverg. ' 3.71 < 3.67 ( J. C. SALA, SAN FRANCISCO 161 T A B L K S POSITION- UK TIIK PRINCIPAL LINES OK THE U. S. SUKVEYS IN THE STATE OF OREGON. | Initial Point, intersection of Willamette meridian and baseline, Lat. 45 31' 13" North; Long. 122 30' 26" West, Surveys north of the Willamette Base Line. Parallel Latitude. Distance Longitude per Range. Converg. Wiihunrtt,- Base Line..... 1 Mamlarti Noitli . ; ii - .. o / // 45 31 13 45 52 04 46 07 42 Miles. 24 42 o / // 7 25.0 7 27.7 7 29.8 Chains. 2.90 2.25 Surveys south of the Willamette Base Line. > " MHes. / " Chain* Willamette Base Line ... 45 31 13 7 25.0 1 Standard South.... 45 05 09 30 7 21.6 3.62 II " " . ... 44 39 03 60 7 18.3 3.59 Ill 44 23 2C 78 7 16.3 2.15 IV 43 57 22 108 7 13.1 3.51 v - 43 36 30 132 o 7 10.6 2.76 vi . ... 43 10 26 i 162 7 07.7 3.41 Vll 42 44 21 192 7 04.6 3.38 VII 1 42 28 42 210 7 02.8 2.00 IX 42 07 50 1 234 i 7 00.4 2.63 North Bound, of Calif 'a., j 42 00 00 243 ! <; 59.5 0.99 162 ILLUSTRATED CATALOGUE OF r r A H L E s . TABLES OF GRADES, Per Mile and per 100 Feet, measured horizontally and corresponding to different Angles of Elevation. 1 - L, Feet Feet Feet Feet Feet Feet Feet Feet ( per mile. per 100 ft. o / per mile. per 100 ft. / per mile. per 100 ft. / per mile. 1 ir'ft '' '( 1. 0.01894 18 27.64 0.5237 54. 1.02273 81. 1.53409; U i 1.636 0.02091 28. 0.53030 55. 1.04167 53 81.40 1.5419 ) t 2. 0.03788 29. 0.54924 36 55.30 1.0472 82. 1.55303S < 3. 0.05682 19 29.17 0.5528 56. 1.06061 54 82.94 1.5710 ( ( 2 3.072 0.0582 30. 0.56818 37 56.83 1.0763 83. L57197\ 4. 0.0757( 20 30.72 0.5818 57. 1.07955 84. 1.5909K c 3 4.608 0.0873 31. 0.58712 58. 1.09848 55 84.47 1.6000 ( 5. 0.09470 32. 0.6060( 38 58.37 1.1054 85. 1.60985Y S 6. 0.11364 21 32.26 0.6109 59. 1.11742 86. 1.62879( 4 6.144 0.1164 33. 0.62501 39 59.90 I.lo45 56 86.01 1.0291 ) 7. 0.13258 22 83.86 0.6400 60. 1.13636 87. 1.64773) 5 7.680 0.1455 31. 0.64394 61- 1.15530 57 87.54 1.6583 ) ) 8. 0.15152 35. 0.66288 40 61.44 1.1636 88. 1.66666) 9. 0.17045 23 35.33 0.6691 62. 1.17424 89. 1.68561) S 6 9.216 0.1746 36. 0.68182 41 62.97 1.1927 58 89.08 1.6873 ) ? 10. 0.18939 24 36.86 0.6982 63. 1.19318 90. 1.70456J 7 10.75 0.2037 37. 0.70076 64. 1.21212 59 90.62 1 7164 S ) 11. 0.20833 38. ).71970 42 64.51 1.2218 91. 1.72348) 12. 0.22727 25 38.40 0.7273 65. 1.2310f 92. 1.74242) )o 8 12.29 0.2328 39. 0.73864 66. 1.25000 1 92.16 1.7455 ( ? 13. 0.24621 26 39.94 0.7564 43 66.04 1.2509 93. 1.76186S 9 13.82 0.2619 40. ).75758 67. 1.26894 94. 1.78030( / 14. 0.26515 41. ).77652 44 67.57 1.2800 95. 1. 79924 ( r , 15. 0.28409 27 41.47 0.7855 68. 1.28788 1 2 95.23 1.8038 f 10 15.36 0.2909 42. 0.79545 69. 1.30682 96. 1.81818? / 16. 0.30303 43. 0.81439 45 69.11 1.3090 97. 1.83712? > 11 16.90 0.3200 28 43.01 3.8146 70. 1.32576 J8. 1.85606? 17. 0.32197 44. 0.83333 46 70.64 1.3381 1 4 J8.30 1.8620 ) ( 18. 0.34091 29 44.54 0.8436 71. 1.34470 99. 1.87500/ , 12 18.43 J.3491 15. X8522'3 72. 1.36364 100. 1.89394) ' 19. 13598-) 46. J.87121 47 72.18 1.3672 101. 1.91288) ; 13 19.90 0.3782 30 16.08 0.8727 73. 1.38258 1 06 101.4 1.9202 ) \ 20. 10.37879 47. 189015 48 73.72 1.3963 102. 1.93182) \ 21. 0.3J773 31 47.62 0.9018 74. 1.40152 103. 1.95076) ( 14 21.50 0.4073 48. 0.90909 75. 1.42045 104. 1.96969) 22. 0.41667 49. 0.92803 49 75.26 1.4254 147. 2.78409S S 23. 0.43561 32 49.16 ).9309 76. 1.43939 1 36 147.4 2.7932 ( ( 15 23.0 i J.4J04 50. ).94697 50 76.80 1.4545 148. 2.80308C 24. 0.45455 33 50.69 0.9600 77. ..45833 149. 2.82197( j 10 J4.58 0.4655 51. 0.96591 78. 1.47727 150. 2.8409K 25. 0.47348 52. 0.98485 51 78.33 1.4837 1 38 150.5 2.8514 ? 26. 0.49242 34 52.23 0.9891 79. 1.49621 151. 2.85985( 17 26.11 0.4946 53. 1.00379 52 79.87 1.5128 152. 2.87879? 27. 0.51136 35 53.76 1.0182 80. 1.51515 1 40 153.6 2.90P? ? J. C. SALA, SAN FRANCISCO I6 3 TABLE. ) TABLE OF UADII, MIDDLE OKDINATES, & c ., OF CURVES. \ S CHORD 100 FKKT. . IT The Tun^ntia] A = Ic is always one-half of the Angle of DcflucMon. Deflw > R:ulit III fi-i-t Deflec. distance in ft. Tunj , dist in for '. Mid Ordi . Aig Defle (.' liadii :' Defle in feet. ;' dist in fee c. Tang dist t. in fee Mid Ordi i. r o / ~ \ 143775 171887 86944 67296 42972 .023 .058 .116 .174 .232 .'114 .029 .058 .087 .116 .004 .008 .014 .022 .028 2 ( in " 18 " 24 " 30 2729 2604 2491 2387 2292 ! 3.66J i 3.8LL : 4.014 : 4.188 i 4.363 1.83i 1.9m 2.007 2.094 2.182 J80 ( .502 .523 .545 \ 14 H :ii:iTK 28648 24666 21485 .291 .349 .407 .465 .145 .174 .203 .232 .036 .043 .050 .058 " C6 "48 " 54 2204 2122 2046 1976 : 4.538 :' 4.712 I 4.886 ; 5.060 2.269 2.356 2.443 2.530 .567 .589 .611 .632 18 19098 .52'{ .261 .065 3 1910 P. 235 2.618 .651 20 17189 .581 .M .073 " 15 176J I 5.C66 2.8C6 .710 2! 15C27 .639 .:i!9 .080 " C-0 1637 i C.108 3.054 .764 ( 24 14:. _'l .,-,1,7 . :!4K .087 " 45 1528 3.272 .818 ) 2) 13222 .756 .378 .095 4 1433 i 0.980 3.490 .873 ( 28 12278 .: ( 48 7162 1.395 .697 174 " 45 849.3 ; 11-78 5.890 1.473 50 6876 1.453 .726 182 7 819.0 i 12.21 6.105 1.528 < 6611 1.511 .755 189 "15 790.8 ! 12.64 6.320 1.582 54 6367 1.569 .784 197 " 30 764.5 i 13.08 6.540 1.67 .; 56 6139 1.627 .813 204 "45 739.9 i 13.51 6.755 1.692 58 5928 1.685 .842 1 .211 8 716.8 i 13.95 6.975 1.746 1 5730 1.745 .872 .218 "15 695.1 i 14.38 7.190 1.801 < 4 5372 i 1.860 .930 .232 " 30 674.6 : 14.81 7.405 1.8C.3 " 8 5056 1.976 .988 .246 "45 655.5 : 15.25 7.625 1.910 ' 12 4775 2.094 i 1.047 .261 9 637.3 i 15.68 7.840 1.965 < 16 4524 2.210 i 1.105 .275 " 15 620.2 i 16.12 8.960 2.019 ( ' 20 4298 2.326 : 1.163 .290 " 30 603.8 : 16.55 8.275 2.074 ( " 24 4093 2.443 ; 1.221 306 " 45 588.4 i 16.99 8.495 1.128 ( ' 28 3907 2.559 i 1.279 .320 10 573.7 ' 17.43 8.715 ; >.183 ( ' 32 3737 2.676 i 1.338 .334 " 15 559.7 17.87 8.935 . " 36 3581 2.793 j 1.396 349 " 30 546.4 18.30 9.150 <. '.2D2 ? I " 40 3438 2.908 \ 1.454 S64 " 45 533.8 18.73 9.365 i .347 ? 44 3306 3.025 i 1.512 . 378 11 521.7 19.17 9.585 J 401 S " 48 3183 3.141 i l.~70 . 393 " 15 510.1 19.61 D.805 2 .456 (, " 52 3069 3.258 i 1.629 . 407 " 30 ' 499.1 20.05 1 0.03 1 .511 ( " 56 2964 3.374 : 1.687 . 422 " 45 ' 488.5 20.50 1 0.25 2 .566 ( ; 2 2865 3.490 : 1.745 . 436 ] 2 i 4 78.U 20.94 1 0.47 2 .620 ( ( ( 164 ILLUSTRATED CATALOGUE OF TABLE. TEMPERATURE OF BOILING WATER Corresponding to the Height of Barometer and Altitude above Sea Level, Thermo. Baro. Alti. Thermo. Baro, Alti. Thermo. Baro. Alti. > Deg. inch. feoi . fi inch. feet. I) eg inch feet. 184.0 16.79 15221 IMfl 20.82 9579 204.6 25.59 4169 .2 16.86 15112 .2 20.91 9466 .2 25.70 4057 > .4 16.93 15003 A 21.00 9353 .4 25.88 3945 .6 17.00 14895 .6 21.09 9241 .0 25.91 3344 } > .8 17.08 14772 .8 21.18 9130 .H 26.01 3742 / 185.0 17.16 14649 195.0 21.26 , 9031 205.0 26.11 3642 ) .2 17.23 14543 .2 21.35 8920 .2 26.22 3532 S .4 17.31 14421 .4 21.44 8810 .4 26.33 3422 5 .6 17.38 14315 .6 21.53 8700 .6 26.43 3322 ( .8 17.46 14195 .9 21-62 8590 .8 26.54 3213 ( 186.0 17.54 14075 196.0 21.71 8481 206.0 26.64 3115 (* ) ' 2 17.62 13956 .2 21.81 8361 .2 26.75 3007 ? 17.70 13837 .4 21.90 8253 .4 26.86 2899 f *6 17.78 13718 .6 21-99 ! 8145 6 26.97 2792 ) .8 17.86 13601 .8 22.08 8038 .8 27.08 2685 ; 187.0 17.93 13498 197.0 22.17 7932 207.0 27.18 2589 S .2 18.00 13396 .2 22.27 7814 .2 27.29 2483 ( .4 18.08 13280 .4 22.36 7708 .4 27.40 2377 ( .6 18.16 13164 .6 22.45 7602 .6 27.51 2272 ( \ .8 18.24 13049 .8 22.54 . 7498 .8 27.62 2167 ( <* 188.0 18.32 12934 isao 22.64 7381 208.0 27.73 2063 <> } -2 18.40 12820 .'2 22.74 7266 .2 27.84 1959 / -.4 18.48 12706 .4 22.84 ; 7151 A 27.95 1856 ( .6 ; 18.56 12593 .6 22.93 i 7048 .6 28.06 1753 ( , ; .8 18.64 12480 .8 23.02 6945 .8 28.17 1650 ( ) 189.0 18.72 12367 19: o 23.11 6843 209.0 28-29 1539 ) .2 18.80 12256 .2 23.21 j 6729 .2 28-40 1437 ) ) .4 18.88 12144 .4 23.31 6617 A 28.51 1336 S ) .6 18.96 12033 .6 23.40 6516 .6 28.62 1235 v ) .8 19.04 11923 .8 23.49 6415 .8 28.73 j 1134 C 190.0 19.13 11799 200.0 23.59 6304 210.0 1 28.85 1025 ( .2 I 19.21 11690 .2 23.69 6193 .2 28.97 910 ( .4 19.29 11581 A 23.79 6082 .4 29.09 808 < .6 19.37 11472 .6 23.89 5972 .6 29.20 709 C .8 19.45 11364 .8 23.98 5874 .8 29.31 610 ? 191.0 19.54 11243 201.T 24.08 5764 211.0 29.42 512 ) .2 19.C2 11136 .2 24.18 5656 .2 29.54 405 ) .4 19.70 11029 .4 24.28 5547 .4 29.65 308 ) ) .6 19.78 i 10923 .6 24.38 5440 .6 29.77 202 S S .8 19.87 1080* .8 24.48 6332 .8 29.88 105 J) \ 192.0 19.96 10685 202.0 24.58 5225 212.0 30.00 sea level. ( .2 20.05 10567 .2 24.68 5119 below se level, ( .4 20.14 10450 .4 24.78 5013 .2 30.12 - 1 4 ( .6 20.22 10346 .6 24.88 4907 .4 30.24 - 206 ( .8 j 20.31 10230 '8 24.98 4802 .6 ; 30.35 -- 304 ( .8 30-47 - 405 ) 193.0 20.39 10127 203.0 25.08 4697 .2 ! 20.48 10011 2 25.18 4593 213.0 30.59 - 512 .4 20.57 9896 .4 25.28 4489 .2 30.71 613 .6 20.65 9794 .6 25.38 4386 A 30.82 714 8 20.73 9693 .8 25.49 4272 .6 30.93 - 813 J. C. SAL A, SAN FRANCISCO TABLE, THERMOMETERS. Corresponding Temperatures by the Fahrenheit, Centigrade and Reaumur Scales. ' lahren . Centi. BflM. Fahren . Centi. Reau Fahren . Centi Reau. ) 212 100.0 ' Dag 80.0 128* 53.3"' De 42. Deg. i Deg 44 67 5.3 \ 210 98.9 ) 208 97.8 79.1 78.2 126. 124 52.2 51.1 41. 40. 42 40 5.5 4.4 4.4 3.5 206 96.7 77.3 122 50.0 40.0 38 3.3 2.6 204 95.6 76.4 120 48.9 39.1 36 2.2 1 IT 202 94.4 75.5 118 47.8 38.2 34 1.1 0.8 2DO 93.3 74.6 116 46.7 37.3 32 0.0 .0 ( 198 92.2 73.7 114 45.6 36.4 30 - 1.1 - 0.8 ( 196 91.1 72,9 112 44.4 35.5 28 2.2 i 1.7 ( ) 194 90.0 72.0 110 43.3 34.6 26 3.3 2.6 ( ) 192 88.9 71.1 108 42.2 33.7 24 4.4 3.5 ) 190 87.8 7C.2 106 41.1 32.8 22 5.5 4.4 j 188 86.7 69.3 104 40.0 32.0 20 i - 6.7 . - 5.3 186 85.6 68.4 102 38.9 31.1 18 7.7 6.1 184 84.4 67.5 100 37.8 30.2 1C 8.9 7.3 182 83.3 : 66.6 98 36.7 29.3 14 10.0 8.0 180 82.2 65.7 96 35.6 28.4 12 11.1 : 8.8 178 81.1 64.9 94 34.4 27.5 10 12.2 9.7 176 80.0 64.0 92 33.3 26.6 8 - 13.3 -10.6 174 78.9 63.1 90 32.2 25.7 g 14.4 11.5 172 77.8 62.2 88 31.1 24.8 4 15.5 12.4 170 76.7 61.3 86 30.0 24.0 2 16.7 13.2 167 75.0 60.0 84 28.9 23.1 o 17.7 14.1 166 74.4 59.5 82 27.7 22.1 2 18.9 15.1 ' 164 73.3 58.6 80 26.6 21.2 4 - 20.0 -16.0 ( 162 72.2 57.7 78 25.5 20.4 g 21.1 16.8 160 71.1 56.8 77 25.0 20.0 8 22.2 17.7 158 70-0 56.0 74 23.3 18.6 10 23.3 18.6 166 68.9 55.1 72 22.2 17.7 12 24.4 19.5 154 67.8 54.2 70 21.1 16.8 14 25.5 20.4 \ 152 66.7 53.3 68 20.0 16.0 16 - 26.7 -21.2 <* 150 65.6 52.4 66 18.9 15.1 8 27.7 22.1 ( 148 64.4 51.5 64 17.7 14.1 20 28.9 23.1 ( 146 63.3 50.6 62 16.6 13.2 2 30.0 24.0 ( 144 62.2 49.7 60 15.5 12.4 4 31.1 24.8 > 142 61.1 48.8 58 14.4 11.5 6 32.2 25.7 ) i 140 60.0 48.0 56 13.3 10.6 8 - 33.3 -26.6 ) 138 58.9 47.1 54 12.2 9.7 34.4 27.5 ) 136 57.8 40.2 52 11.1 8.8 2 35.6 28.4 134 56.7 45.3 50 10.0 8.0 4 36.7 29.3 132 55.6 44.4 48 8.9 7.3 6 07.8 30.2 130 54.4 43.5 46 7.7 6.1 8 38.9 31.1 / r66 ILLUSTRATED CATALOGUE OF TABLES. Equivalents of Lineal Measures. ^ Inches. Links. Feet. Varas. Yards. Chains. | Miles. SjT Lea. Eng,Lea.( ', 1 0.12G2G3 0.083333 0.029965 0.027778 0.001263 0.000010 0.000006 0.000005 ( "7.92 1 0.66 0.237325 0.22 0.01 0.001)125 0.000047 0.000042 ( ia ) 33.372 1.515152 4.213636 2.781 0.359583 1 0.333333 0.927 0.015152 0.000189 0.042136 0.000527 0.000072 0.0002 0.000063 ( 0.000176 ; \36 4.545455 ;j 1.078749 1 0.045455 0.000568 0.000216 0.000189 / i792 100 66 23.73247| 22 1 0.0125 0.01)4746 0.004167 ) ',63300 8000 5280 1898.598 1760 80 1 0.379720 0.333333 , U 66860 210(58.18 13905 5000 4635 210.6818 2.63H52 i 1 0.877841 ' ' 190383 24000 15840 5695.793 5280 240 |3 1.139159 1 ( Equivalents of Square Measures. ; Varas. Yards. Chains. Acres. Miles. Sp. League! Eng. Lea. , \ i 0.859329 0.00177547 0.00017755 0.00003328 0.00300304 0.00000303 "1.16369865 1 0.032[>6612 0.00020661 O.();)003332 0.00000005' 0.00000004 }563.230148 484 1 0.1 0.0001H625 0.03002253 0.000017o6 ) 5632.30148 \3604672.95 4840 3097600 10 6400 640 0.0015625 0.00022533 0.00017361 ) 0.14418092 0.11111111 ) \25000000 21483225 44386.8285 '4438.68285 6.93544195 1 0.77060466 ^32442056.5 27878400 57600 5760 9 1.29768226 1 FrencJi Units of Weights and Measures, &c. MKTUIC. , MEASURES OF LENGTH. ) Myriametre. . . .10000 meters r Kilometre 1000 " ( Hectometre .... 100 )Dekametre 10 " , Metre 1 - Decimetre... one-tenth " 1 Centimetre... one 100th " Millimetre.. one 1000th " I Kilometre . . . .3-280.833 feet 1 Hectometre. . . .32S.OS3 feet GRAMME. LlTHK. WEIGHTS. Millier . 1000000 Grammes MEASUKES OF VOLUME. Kilolitre lOOOlitre I 8 Quintal.... 100000 Hectolitre 100 " ) Myriagram' 10000 Kilogram' 1000 ** Decalitre 10 " Litre .. 1 " I Hectogram ' 100 " Decilitre one-tenth " ? Dekagram'. 10 Centillitre.... one 100th " ( ( Gramme... 1 Millilitre.... one 1000th " Decigram', one-tenth " 1 Fluid Dr'in.,0, (ll): '''''-"' 7 " I Centigram. one 100th " 1 Fl.()unc.e...0.02'.i.'." - !'.t " \ Milligram'. one 1000th " 1 !'!. Found. ;!54S3050 " \ CUBIC WEIGHT. CUBIC MEASUKE. f 1 Cubic M. 2204 (i Ibs. A O 1 Cub.M. ..204.17 wiiu-ga \ MEASURE OF SUKKACE. Hectare... .10000 Sq. Meters Hectarc 2.471 aeres 1 Cub. Litre, 2.2040 " " i 1 Cub. Litre.l.05G7 wine gal Are..". 119. Sq. Yard s , Tonncau. .1000000 gr'nni.es. J. C. SALA, SAN FRANCISCO I6 7 Inches. | Links. 7.92 12 36 7'.)2 39.37 0.126263 1.515152 4.545455 100 8000 4.9710591 Inches. 637364 '6272640 ,'1550.0581)477 TABLES. Equivalents Lineal Measures Feet. O.OH3333 0.63 3 66 5280 3.280899 Yards. I Chains. Miles. 0.000016 , , 0.000125 0.333333 j 0.015152 ' 0.000189 0.027778 ! 0.001263 (1.22 (1.01 1760 1.093633 0.045455 0.0497106 0.0006213 Meters. 0.02540005 0.20116839 0.3048006 0.000568 I 0.9144018 20. 11683!) 6 1609.347168 1 0.0125 1 Equivalents of Square Measures. Feet. 0.0069444 1 9 4356 4356G 10.7642982 0.0007716 10.333333 484 4840 1.11)61331 Chains. 0.0000016 (0.0002296 10.00206612 1 (10 0.0024711 Meters. 0.00000016 0.000645161 0.9000229 Equivalents of Weights. 0.1 0.00024711 0.092903184 404.671063 4046.71063 1 7.21875 ^ 28.875 S 57.75 231. 61.0165 ( 1 2 4524 '0.25 ^ 1 2.1131 0.125 0.50 1.05656 0.1182955 0.4737821 0.9463642 3.7854579 1 A standard avoirdupois pound is the weight of 27.7015 cubic inches of distilled ', water, weighed in air at a temperature of 39 . 83 Fahrenheit, barometer at 30 inches. ) A cubic inch of such water weighs 252.6037 grains. ^ A cubic foot contains 7.48052 gallons liquid measure. A gallon is equal to a / cylinder of 7 inches in diameter and 6 inches high. ( INDEX A PAGE 78 Compass Prismatic evel 5O Solar lane Table 64 Surveyors'. extant olar Compass. . . . ransit er. . 66 59 44 10 84 " Vernier D Dividing Kngine, Automatic. jsting Magnetic) [etal J 16 Dumpy Level Drawing Materials . . 72 Instruments i . . 6s Abney's Level. . . . Adjustment of Level < < Aluminum . . Aneroid Barometer. . Apparatus for Testin Influence on Metal . Arrows ..... Artificial Ho Astronomical Telescopes ......... 103 Attachments of the Transit ....... 32 Automatic Dividing Kngine ....... 15 PAGR . 60 57 53 55 15 49 93 99 B Bags, Gossamer and Silk ...... Barometers, Aneroid Surveying. . . " Weather .... Mercurial Standard .... Black Process Paper ........ ...... Blue " ............. Books on Engineering and Sur- )_ veying ....................... j 90 84 105 106 94 93 t Brushes for Cleaning Instruments. 90 Camera Lucida 90 Care of Instruments 19 Cases for " 13 Centering Apparatus 16 Centers of Instruments 27 Chains. . . 73 Clamps and Tangent Screws 31 Clinometers, Attwood 80 Clinometer Rule 79 Cloth Finish of Instruments 12 Collar Tester 19 Collimator Apparatus 17 Compass (on Transit) 30 " Clinometer 5 6 Pocket 57 Plain . 55 Engineers' Level. . . Transit. . Errors of Compass . Extension Tripods . 47 36 54 3' Field Books for Engineers and 1 Surveyors \ - Field Glasses 86 Finish of Instruments 12 Flexible Rods. . . 72 Graduations Gradienter Screws " Screw Tables Ground Bubbles H Hand Level Heliographs Hydrographic Level Hydrometers Hygrometers Latitude Coefficients Level 25 32 140 105 78 103 50 106 106 116 47 INDKX CONTINUED PAGE Level, Abney's 78 ' ' Architects' 49 " Dumpy 49 ' ' Engineers' Y 48 1 ' Farmers' 49 " Hand 78 ' ' Hydrographic 50 " Locke's 78 ' ' Pocket 78 ' ' Rod 90 1 ' Reversion 50 " Sala's Telescopic Hand 79 " Tape 77 ' ' Trier Leveling Screws Rods Longitudinal Dividing Engine Lubricants 90 M 89 Magnifying Glasses Making and Repairing of Instru- \ ments ) Marine Glasses 86 Meridian by two equal Altitudes. . 142 Mining Transit 40 Mountain Transit 40 O Odometer, Sala's Offset Attachment to Transit. Optical Square 81 39 67 Packing Instruments. . . . . . 14 Plate Levels . . . .27 Pantograph . . . QS Parallel Rulers 98 Passometer Pedometer 81 Si Pins 73 Plane Table .... 62 Planimeter. QS Plumb Bobs 82 Plumet Lamp, Sala's Pocket Compass " Level.. 83 61 . 78 Pocket Magnifiers 89 Preface 8 Protractors 95 Draughtsmen's 96 Boxwood 97 Kern's Vernier 96 Rain Gauges Refraction Table Repairing Instruments Rods, English self-reading. . . . " Flexible " Flynn's ' ' Iron Tubular " Line ' ' Metric . . " New York " Philadelphia , " Sala's self-reading " Steel Line Rules, Stephen's Combination " Clinometer.. Saegmuller's Solar Attachment Scales, Flat and Triangular. . . . <( Rule Sextant, Marine Pocket Slide Rules, Stadia Solar Attachments Spy Glasses Stadia Surveying Standards Standard Steel Tapes Straight Edges T Squares Table of Refractions in Declina- tion for Solar Compasses Table of Increase or Decrease of the Sun's Declination Table of Azimuth of Polaris " Length of a Degree of Lat- itude. . 104 117 13 71 7i 72 7i 71 72 71 71 72 7i 90 79 109 97 98 65 66 98 33 89 126 30 75 .. 98 }i44 }i45 . . 146 }iso INDEX CONTINUED rrvvjc Table, Length of a Degree of) Longitude j 5 Table, Divergency of the Parallel ) of Latitude ! I54 Table, Reducing Chains to Feet. . . 155 of Acres required per Mile i and per 100 feet for different L 155 widths J Table, Trigonometrical Series 156 of Solution of Triangles. . . . 157 " for Running Slopes 157 " Geographical Position of) o Standard Lines in California. . / T ^ Table, Geographical Position of) Standard Lines in Nevada. . . . j I ^9 Table, Geographical Position of) Standard Lines in Utah j I59 Table, Geographical Position of\ .- Standard Lines in Montana. . . / Table, Geographical Position of) ^ Standard Lines in Washington ) Table, Geographical Position of) ^ Standard Lines in Arizona. ... j' Table, Geographical Position of) , Standard Lines in Oregon / Table of Grades 162 " Radii, Middle Ordinates, ) etc. , of Curves i Table, Temperature of Boiling | Water corresponding to Alti- > tude J Table, corresponding Tempera- j tures by the Fahrenheit, Centi- , grade and Reaumur Therrnom- j eters J Table, Equivalents of Lineal ) Measures ) Table, Equivalents of Square ) Measures ) Table, French Units of Weights) j66 and Measures 1 Table, Equivalents of U.S. stand- ) j6 ard and Metric Lineal Measures ) 163 164 165 166 1 66 Table, Equivalents of U.S. stand- ) , ard and Metric Square Measures j l ' Table, Equivalents of U.S. stand- ) , ard and Metric Liquid Measures j ' Tangent Screws and Clamps 31 Tapes, Chesterman's 74 Eddy's 75 " Metallic Warp 77 Paine's 75 Rival 76 Telemeter 67 Telescope 29 Astronomical 103 Binocular 88 Aluminum 88 Thermometers 106 Thumb Tacks 93 Timber Scriber 90 Topographical Surveying 120 Tracing Cloth 93 Paper -93 Transit (description) 25 Solar . combined Mining and 39, 40 Transit, Engineers' 34, 3 6 > 37 " Light Mountain 4 2 " Small Mining 43 " Surveyors' 3 8 Transportation of Instruments 14 Triangles 9 8 Tripods 3 1 " Sala's Extension 105 < Attachment 29 Verniers Variation Arc 25 39 77231 THE UNIVERSITY OF CAUFORNIA LIBRARY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. OCT 17 1933 217 The Above Cut Represents the Mining- Transit as Used with Saeg-muller's Solar Attachment. tl, ill J. C. 429 Montgomery Street, San Francisco, Cal.