UNIVERSITY OF CALIFORNIA 
 AT LOS ANGELES 
 
 GIFT OF
 
 Analysis of White Paints 
 
 A COLLECTION OF NOTES ON 
 
 THE CHEMICAL ANALYSIS 
 
 OF WHITE AND TINTED PAINTS 
 
 George H. Ellis, B. Sc. 
 
 ANALYTICAL CHEMIST AND ASSAYER 
 
 . . . Late Chemist . . . 
 
 Chicago, Burlington & Quincy R'y Co. 
 
 The Technical Press, Evanston, III.
 
 Copyrighted by 
 
 GEORGE H. ELLIS 
 
 1898
 
 TP 
 936 
 
 PREFACE. 
 
 E following- pages appeared originally in the columns 
 of the "Paint, Oil and Drug- Review," and they are 
 now offered in book form at the request of chemists and 
 v many others in the paint trade. 
 
 V 
 
 While there has been much literature published in the 
 
 ^ technical and trade journals, yet there is no volumn which 
 
 treats solely of the chemical analysis of paints, and it is 
 
 v hoped that this little book may at least partially fill 
 
 the place. 
 
 The author wishes to here express his obligations for 
 
 C valuable advice and the many suggestions offered by Mr. 
 
 ; Walter Lee Brown, Prof. J. H. Long, Mr. Roger S. Pitkin, 
 
 X and particularly to Prof. Vernan J. Hall for his careful 
 
 *v^ revision of proof. G. H. E. 
 
 Chemical Laboratory, 
 May, 1899. 
 
 2G2460
 
 CONTENTS. 
 INTRODUCTORY REMARKS. 
 
 CHAPTER I. 
 
 TAG* 
 
 Preparing- samples for analysis 
 
 CHAPTER II. 
 White Pigments. 
 
 1. Calcium Carbonate ............................................ 7 
 
 2. Gypsum ..................................................... 10 
 
 3. China Clay ................................................... 10 
 
 4. Silica ......................................................... 15 
 
 5. Barium Sulphate ............................................. 16 
 
 6. Magnesium Carbonate.. ..................................... 17 
 
 7. Magnesium Silicate .................................... ...... 18 
 
 8. Zinc Oxide .................................................. 19 
 
 9. White Lead ........................... ................. ...... 24 
 
 CHAPTER EL 
 White and Tinted Paints. 
 
 1. Qualitative analysis of White or Tinted Paints, Paste Paints, 
 
 Fillers and Enamel Paints ............................... 31 
 
 2. Quantitative analysis of White or Tinted Paints, Paste 
 
 Paints, Fillers and Enamel Paints. Scheme 1 ............ 38 
 
 Scheme II ........... 44 
 
 4. Analyses of " Ready Mixed Paints " ......................... 47 
 
 5. Analyses of White Paste Paints ............ ................. 48 
 
 APPENDIX. 
 
 1. Estimation of Turpentine, Benzine and Water ................ 49 
 
 2. Estimation of Linseed Oil in Flax Seed and Oil Cake ......... 52 
 
 3. List of the Principal Pigments, with Chemical Formulae and 
 
 Trade Names ............................................ 54 
 
 4. Table of Atomic Weights .................................... 56 
 
 5. Measures and Weights ..................................... 57
 
 INTRODUCTORY REMARKS. 
 
 My object in sending forth the following pages is to 
 place in the hands of chemists and those interested in paints 
 and pigments, a guide for the practical analysis of such pro- 
 ducts. I make no pretensions to having placed herein much 
 of original matter, but have drawn freely from the records of 
 chemical literature and authorities on the subject, to which I 
 have added such other matter as my experience as au ana- 
 lytical chemist would warrant. 
 
 My aim has been to detail methods for the analysis of 
 the majority of white and tinted pigments and pigment mix- 
 tures found in the paint trade, and which the chemist may be 
 called upon to examine. 
 
 It is assumed that the chemist is familiar with the ap- 
 paratus, reagents, etc., that are required in analytical chemis- 
 try, and for this reason their descriptions are omitted. 
 
 It has been my endeavor to give such methods and in 
 sufficient detail that those having but a limited knowledge of 
 the principles of analytical chemistry could successfully 
 carry out the analyses. In this class there may be some in 
 the paint trade who have sufficient knowledge of analytical 
 chemistry to perform analyses and obtain results for their 
 own use. To these I would respectfully suggest that the 
 details of each determination be thoroughly studied in the 
 standard works, such as Fresenius, in the hope that such 
 research and practice may lead to that proficiency which be- 
 longs to the technical chemist. 
 
 For the guidance of those having but a limited experi- 
 ence the following general precautions are given: 
 
 1st. Generally the reagents used should be those known 
 as chemically pure (c. p.) Should the standard chemicals 
 of known purity be not at hand then the reagent should be 
 especially tested and if found impure be rejected. Or if 
 desired, it may be purified.
 
 _ 2 
 
 2nd. Uee reagents intelligently. Too much as well as 
 too little may cause errors. Study the reaction and the suc- 
 cessful conditions required. 
 
 3rd. All distilled water should be tested for mineral 
 salts. This may be done by evaporating several litres to dry- 
 ness and should leave no perceptible residue. 
 
 4th. The amount of sample taken for analysis should be 
 governed by the amount present of the constituent sought. 
 in general one gram is a sufficient amount, but often times, if 
 the constituent be but a trace, five times or more may be 
 necessary to get a sufficient weighing amount. And again it 
 may be that only a fraction of a gram will give a precipitate 
 of sufficient size for easy manipulation. 
 
 5th. If a determination requires a special apparatus, 
 first make a blank test or test with a substance containing the 
 constituents of known amount, to make sure that the appara- 
 tus is in perfect working order. In fact all determinations 
 may be practiced, using substances of known percentages. 
 
 6th. In using filter paper the size 9 c. m., S. and S. is to 
 be preferred, requiring no correction, as they are practically 
 ashless. If cheaper grades be used, always deduct the ash 
 content. Little time is saved by using large filters as they 
 require more washing and thereby increase the volume of the 
 filtrate. The Gooch crucible and cone are recommended 
 whenever admiesable.
 
 CHAPTER I. 
 
 PREPARING SAMPLES FOR ANALYSIS. 
 
 If the sample is in the form of a mixed or paste paint it 
 will be advantageous to first free the pigments from the 
 mixing fluid. This may be done in several ways. 
 
 When only the analysis of the pigments is desired the 
 simplest method is to wash out or exhaust the oil and thin- 
 ness by benzine, gasoline, petroleum- ether, benzole, ether, etc. 
 As benzine or gasoline are the cheapest they are to be pre- 
 ferred. About 25 grams of the sample, previously thoroughly 
 stirred, are placed in a beaker of about 150 c. c. capacity (or 
 a whisky glass with thin sides) and after adding the solvent, 
 the mass is stirred with a glass rod and the pigment allowed 
 to settle. When the liquid is perfectly clear draw off the 
 clear portion by means of a pipette, again add the solvent, 
 stir and allow to settle. Usually three or four applications 
 of the solvent will be found sufficient to free the pigment 
 from oil and most of the drier. Any traces of the latter are 
 disregarded. It is a good plan to test the solvent after the 
 second treatment by evaporating a small portion on a watch 
 crystal and observing whether it leaves any residue of oil. 
 When ether is not used it is a good plan to finish the extrac- 
 tion with it. After drawing off the solvent as closely as 
 possible the remainder is evaporated on a water bath and the 
 residue heated in an air oven at 100 C. for about an hour. 
 Eemove the dry pigment to a glass or agate sorter, rub up 
 thoroughly and pass through a fine seive. Place in a well- 
 stoppered bottle and label. 
 
 Should the sample be dry or not mixed with oil it is best 
 to heat in the air oven at 100 C. in order to free it from 
 moisture. Then place in bottle and keep stoppered. 
 
 If it is desired to ascertain the percentage of pigments 
 and mixing fluid it may be done by weighing the beaker and
 
 4 
 
 rod, then weighing again after adding the sample, the increase 
 in weight being the amount of sample. Then, after exhaust- 
 ing and drying, the difference in weight is the amount of 
 mixing fluid. 
 Example: 
 
 Weight of beaker rod and sample .............. 42.0771 grams. 
 
 Weight of beaker and rod ...................... 28.6435 
 
 Weight of sample ....................... 13.4336 " 
 
 After treating with solvent: 
 
 Weight of beaker, rod and sample .............. 42.0771 grams. 
 
 Weight of beaker, rod and pigments ....... ____ 36.0520 " 
 
 Loss equals mixing fluid ................. 6.0251 " 
 
 then - = 44.858 percentage mixing fluid by weight. 
 
 When it is necessary to be extremely accurate iu getting 
 both the percentages of mixing fluid and pigment it will be 
 found best to exhaust the sample in a Soxhlet extractor, using 
 petroleum-ether or ordinary sulphuric ether as a solvent. 
 A convenient size of Soxhlet extractor is one inch diameter and 
 nine inches in length with the arrangement as shown in the 
 cut on page 5. The inside tube is an ordinary test tube with 
 a hole cut or blown in the bottom. The bottom of the tube is 
 then packed with a piece of cotton (6). The tube (12) and 
 cotton are weighed first, then the sample of the paint is 
 added, and the whole weighed again, the increase being the 
 weight of sample taken. Another plug of cotton will be found 
 necessary in cases when the pigment is so light that it floats 
 to the top of the test tube. This occurs usually when the 
 cotton is packed too tightly to permit the solvent to flow out of 
 the bottom and often times it will be necessary to place a 
 small glass stopper on the upper layer as a weight to prevent 
 the contents of the tube from overflowing or floating to the 
 top. When such an arrangement is necessary the whole tube, 
 including sample and two plugs of cotton, are weighed, but 
 not the glass which was added as a weight. About an ounce 
 of the solvent, ether or petroleum-ether, is then placed in the 
 flask and the water heated in the water bath not quite to 
 boiling point. Soon the ether will begin to appear in the
 
 5 
 
 condenser and drop back in the test tube containing the paint, 
 and, passing down through the 
 sample, will fill up in the tube 
 (13) and syphon over. This 
 operation is kept up until the 
 solvent liquid is perfectly clear 
 and shows no color, which, in 
 most cases, would be due to oil. 
 Usually about a dozen syphon- 
 ings will be sufficient, but sam- 
 ples vary and it is best to allow 
 the extractor to work until the 
 solvent syphons perfectly color- 
 less. The test tube (12) con- 
 taining the oil-free paint is now 
 removed and thoroughly dried 
 in a drying-oven then weighed. 
 
 The loss in weight equals the 
 oil present, and the dried sam- 
 ple is taken out to be used for 
 the analysis. If it is desired to 
 find the amount of oil, the small 
 flask (8) may be weighed before 
 the operation and then the ether 
 evaporated on a water bath heat- 
 ed in an air oven at 100 C, for 
 15 minutes, and the amount of 
 the extracted oil weighed. 
 
 The centrifugal machine, such 
 as is used in the separation of fat 
 in milk, may be utilized to advan- 
 tage in separating the pigment 
 
 .. _ from the oil and thinners. This 
 
 is accomplished by using from 
 
 2 waflr ?niet et ! WateSh five to ten grams of the sample, 
 and, after placing in the tube, 
 add gasoline to within a half 
 inch from the top. Then with a 
 glass rod stir the whole until the 
 
 sample is thoroughly mixed with the benzine. Place in 
 
 5 Sample Paint 
 fi Cotton Plug 
 7 Cork Stopper 
 
 12 Test Tube 
 
 13 8oxWet Tube
 
 6 
 
 machine and revolve about ten minutes or until the benziue 
 is clear and free from the suspended pigment. Pour off the 
 benzine, which is readily done as the pigment will be thrown 
 to the bottom of the tube and forms a hard cake. Now add 
 more benzine, and, with the aid of a glass rod, again stir 
 thoroughly and revolve as before. Generally three or four 
 treatments will complete the extraction. When the pigment 
 is removed with the aid of a spatula and transferred to a 
 watch glass. Then dried, sifted and bottled. 
 
 This method may be found of much value in a labora- 
 tory where many ground or mixed paints are daily examined 
 and quick results desired. 
 
 It is the practice of some paint chemists to treat the sample, if it 
 be mixed with oil, with strong nitric acid, to which is added about one- 
 fourth water, and boil. Ihe oil collects in a gummy mass and is filtered 
 after diluting. Wash the filter with hot water acidulated with nitric 
 acid. The filtrate will contain soluble pigments and the insoluble por- 
 tion will remain on filter with the oil. 
 
 This method is not to be recommended except in cases where a 
 rough test is deeired to ascertain the bases present.
 
 CHAPTER II. 
 
 WHITE PIGMENTS. 
 
 i. Calcium Carbonate, ( Whiting. ) Whiting consists 
 of carbonate of calcium (CaCO 3 ), with small amounts of 
 magnesium carbonate, silica, iron and alumina, moisture and 
 possibly sulphate of calcium. The analysis is not often re- 
 quired as its cheapness offers no inducement for adulteration, 
 yet the paint manufacturer or chemist may be called upon to 
 choose between several samples and a plan for its examina- 
 tion is herewith given. 
 
 Moisture. Take about two grams on a watch glass, 
 weigh carefully, place in an air oven, and heat at a temperature 
 of 100 C., until the weight is constant. The loss is the 
 moisture. 
 
 Silica and Insoluble Matter. Dissolve one gram of the 
 dried sample in a 200 c.c. covered beaker with about 10 c.c. 
 strong hydrochloric acid and 100 c.c. of water. When effer- 
 vesence is over and a white insoluble residue appears, it 
 indicates that silica is present. Transfer to a platinum dish 
 and bring to dryness on a water bath, then heat in an air oven 
 at 100 C., to drive off all the water and and render the silica 
 insoluble. When the smell of hydrochloric acid has disap- 
 peared, remove from oven and moisten with hydrochloric 
 acid, then add about 30 c.c. water and heat until everything 
 but silica is dissolved. This will settle to the bottom and is 
 filtered off on a small ashless filter and washed with hot water. 
 Allow to drain well in funnel, place filter in a weighed plat- 
 inum crucible and ignite until nothing but the white silica 
 (SiO 2 ) remains. In igniting a wet or moist precipitate a little 
 skill is required to prevent loss from spirting. If the opera- 
 tor will be careful to incline the crucible on the triangle, and 
 allow the gas flame to play on the outer edge first, and grad- 
 ually heat the whole crucible until the paper becomes charred,
 
 8 
 
 forming a sort of envelope with the precipitate inside, no 
 trouble will be occasioned from loss and the paper will 
 gradually burn away. The precipitate is then cooled in the 
 dessicator and weighed. 
 
 Iron and Alumina. To the filtrate add a few drops of 
 nitric acid, wRrru to oxidize the iron, then add 5 grams chemi- 
 cally pure s ammonium chloride, then ammonia in excess and 
 boil until excess of ammonia is driven off. Filter, wash with 
 hot water an$ ignite the wet precipitate as in silica determina- 
 tion. Should a/?hite flocculent precipitate appear, it shows 
 that enough aticfrnonium chloride has not been used to prevent 
 the calcium from precipitating as hydrate, and it will be 
 necessary to keep adding ammonium chloride until nothing 
 but iron and alumina are thrown down. Weight equals iron 
 oxide and alumina (Fe 2 O 3 and A1 2 O 3 ). As the amount of 
 iron and alumina is very small in whiting, it will not be 
 necessary to separate them. 
 
 Calcium Carbonate. To the filtrate from the iron and 
 alumina add ammonia in excess. Now add drop by drop and 
 with constant stirring, ammonium oxalate (about 40 c.c. 
 saturated solution ) until the precipitate csases to form and 
 the ammonium oxalate is in considerable excess. It is neces- 
 sary to add a sufficient amount to combine with the magne- 
 sium as well as the calcium. Allow the precipitate to settle 
 in a warm place for several hours, preferably over night. 
 Then pour the clear supernatant fluid through an ashless filter 
 until the precipitate is covered with about a half inch of the 
 liquid. Add hydrochloric acid until the precipitate is dis- 
 solved, then 40 c.c. hot water, ammonia in excess, add 5 c.c. 
 ammonia oxalate, stir well and allow to stand again for 
 several hours and filter. The filter is washed well with hot 
 water and then dried. The object in dissolving and reprecip- 
 itating the calcium oxalate is to make sure that no magne- 
 sium is precipitated. In whiting it is not absolutely neces- 
 sary, as the magnesium, if any is in small amounts, but in 
 cases where much magnesium is present, it is quite essential 
 for complete precipitation. Proceed with the filtrate as 
 directed in magnesium determination. 
 
 The dried calcium oxalate may be weighed either as 
 calcium oxide or calcium sulphate. If the former method is
 
 9 
 
 to be used the ordinary heat of a Bunsen burner will not be 
 sufficient to drive off all the carbon dioxide, and it will be 
 necessary to heat over a blast lamp until after several weigh- 
 ings, the weight is constant. The weight of calcium oxide 
 (Cap) multiplied by 1.784 gives the CaCO, or carbonate of 
 calcium. If the calcium oxalate is to be converted to calcium 
 sulphate proceed as follows: Moisten the dried precipitate 
 of calcium oxalate with dilute sulphuric acid (1 part acid, 
 3 parts water) and heat cautiously until the excess of acid is 
 driven off and the precipitate is white. Cool. Add a few 
 drops of concentrated sulphuric acid and again heat cautiously 
 by allowing the gas flame to play gently back and forth on 
 the crucible until the white fumes are entirely driven off. 
 Next heat to rednees for about five minutes, cool and weigh. 
 The weight of calcium sulphate multiplied by .7349 gives 
 the CaCO 3 . 
 
 Magiiesium Carbonate. To the combined filtrates from 
 the calcium oxalate precipitate add a large excess of ammonia 
 until it is strongly alkaline, then an excess of a solution of 
 sodium phosphate, stir well without permitting the rod to 
 touch the sides of the beaker, allow to stand 12 hours (best 
 over night) in a cool place, filter and wash with ammonia 
 water (1 part ammonia, 2 parts water.) If the combined 
 filtrate exceeds 100 c.c. add hydrochloric acid in slight 
 excess, evaporate to 100 c.c., cool and proceed as above. A 
 rubber tipper rod will be found very useful to rub the crys- 
 talline precipitate from the side of the beaker. Dry. Be- 
 move precipitate from paper with a spatula to a piece of 
 black glazed paper, then burn the paper first in a weighed 
 porcelain crucible, cool, add precipitate and ignite strongly 
 until the precipitate is white or nearly so, and has a constant 
 weight Weigh the magnesium pyrophosphate (Mg 2 P 2 O 7 ) 
 and multiply by factor .7575 to convert to MgCO 3 . 
 
 Sulphate. To estimate any sulphuric acid that might 
 be present as sulphates proceed as follows: 5 grams of the 
 sample are dissolved in hydrochloric acid and any insoluble 
 matter filtered off and the filter washed with hot water. To 
 the warm filtrate, add drop by drop with constant stirring, a 
 solution of barium chloride until the precipitate ceases to 
 form and the precipitant is in excess. Allow to stand in a
 
 - 10 - 
 
 warm place over night, filter, wash with hot water and after 
 the preciDitate is drained well, ignite as in silica determination. 
 Weigh the white precipitate of barium sulphate (BaSO 4 ) and 
 multiply by factor .583 to convert to calcium sulphate (CaSO 4 ) 
 Then multiply the calcium sulphate found by factor .735 to 
 convert to calcium carbonate, subtract this from the total 
 calcium carbonate and the difference is the amount of 
 calcium carbonate. 
 
 2. Gypsum (Sulphate of Calcium, Terr a Alba). Gypsum 
 is found quite abundantly and often in a state of great purity. 
 It has the chemical composition of CaSO 4 2H 2 O, and if the 
 water be driven off by heat the well known Plaster of Paris 
 will be left, which has the property of again combining with 
 water to "set" into a white hard mass. When used as a pig- 
 ment gypsum is usually fully hydrated. 
 
 Its analysis is not attended with any difficulty. The deter- 
 minations ordinarily to be made are: insoluble matter, (such 
 as clay, sand, etc., ) calcium, sulphuric acid, water and any 
 small amounts of iron and alumina or magnesium. Proceed 
 as directed on page 7 in the analysis of whiting for the deter- 
 minations of soluble matter, iron and alumina, calcium and 
 magnesium, and sulphuric acid. To determine water, use 
 one gram and ignite in a platinum erucible to constant weight. 
 For sulphuric acid determination use 1 gram instead of 5 as 
 in whiting. 
 
 The bases and acids in gypsum are usually reported 
 without combining them: 
 
 ANALYSES OP NATURAL GYPSUM BY THE AUTHOR. 
 
 No. i. No. 2. 
 
 Calcium Oxide 32.88 32.32 
 
 Sulphuric Acid 45.79 45.76 
 
 Water 20.98 21.39 
 
 Silica c undet .07 
 
 Iron Oxide undet .01 
 
 99.65 99.55 
 
 3. China Clay (Kaolin.) China clay is a natural pro- 
 duct and is essentially a hydrated silicate of alumina of the ap- 
 proximate composition, silica 47 per cent, alumina 40 per cent, 
 and water 18 per cent., and has a formula 2 SiO 2 A) 2 O 3 2H 2 O. 
 It is not, however, of constant composition as clays from
 
 11 
 
 different localities vary and usually contain small quantities 
 of iron oxide with calcium, magnesium, potassium and sodium 
 silicates. 
 
 The following is the method of analysis: 
 
 The sample after being pulverized and dried at 100 CL, 
 for about &n hour is kept in a well stoppered bottle. As clay 
 is only slightly acted on by acids, it will be necessary to fuse 
 it to effect decomposition. 
 
 Proceed as follows: 
 
 Silica* One gram is thoroughly mixed in an agate 
 mortar with 10 grams sodium carbonate and about a half 
 a gram of potassium nitrate and placed in a capacious 
 platinum crucible and covered. The mixture should not fill 
 the crucible more than half fall. Fuse over the blast lamp, 
 run it carefully up the sides of the crucible, and when the 
 fused mass is quite clear and quiet, allow to cool. Place the 
 crucible and cover in a beaker, add water until the crucible is 
 just covered and digest on a hot plate until the fused mass 
 is thoroughly disintegrated. Remove the crucible ( and cover ) 
 wash inside and out with hot water, allowing the washings to 
 run back in the beaker. Pour the solution into a, good sized 
 platinum dish, cover witli a watch glass, and then add care- 
 fully, by raising the watch glass a little, hydrochloric acid in 
 slight excess. Add a few drops of hydrochloric acid to the 
 crucible and wash into the platinum dish. The cover should 
 also be clean. After the effervesence is over, wash off the watch 
 glass with hot water and place the dish in a hot air oven or 
 on water bath and evaporate to dryness. It may be necessary 
 to break the crust occasionally by stirring with a platinum 
 rod which is afterward washed, the washings going into the 
 dish. Dissolve the dried mass in water and again bring to 
 dry ness and heat in oven at about 110 C., until all smell of 
 hydrochloric acid is gone. Then add 10 c.c. strong hydrochloric 
 acid and about 100 c.c. hot water. Warm. Filter off the 
 insoluble silica, washing with hot water acidulated with a 
 little hydrochloric acid, dry, ignite first with Bunsen then 
 over the blast and weigh. Weight equals silica (SiO 2 ). 
 
 Oxide of Iron and Alumina. Acidulate the filtrate from 
 the SiO 2 with hydrochloric acid and concentrate to about 
 100 c.c. then add ammonia in slight excess. Boil until it smells
 
 12 
 
 bet slightly of it and allow to settle. Pour off the clear super- 
 natant liquid, add about 100 c.c. of hot water, allow to settle and 
 again decant. Eepeat several times, stirring the preci- 
 pitate and added water each time, then transfer precipitate 
 to a filter using hot water and rubber tipped rod to clean the 
 precipitate from the beaker. Wash precipitate once or twice 
 with hot water, then drain well and ignite wet. Weight 
 equals Fe ? O 3 -\-A\yO 3 > If it is desired to get the oxide of iron 
 and alumina separately, mix the oxides with about 8 times 
 their weight of carbonate of soda in a platinum cruc ble and 
 fuse over the blast lamp. Digest crucible and contents in 
 hot water, and when the fused mass is softened throw on 
 filter and wash slightly with water, then dissolve in hydro- 
 chloric acid and estimate the iron in the solution either griv- 
 imetrically or volumetrically by permanganate or bichromate 
 of potash. 
 
 The gravimetric method is often more convenient on 
 account of its weighing the iron direct. In this method, after 
 fuzing the oxides, filtering, washing and dissolving in hydro- 
 chloric acid, the iron is separated from the alumina by preci- 
 pitation with ammonium sulphide. Add to the solution con- 
 taining the iron and aluminum as chlorides about five times 
 the weight of the oxides, of citric acid, and excess of ammonia. 
 The solution should remain perfectly clear. If it does not 
 remain BO add hydrochloric acid in slight excess, then a few 
 grams more of citric acid and excess of ammonia. Now heat 
 the clear solution to boiling and add solution of sulphide of 
 ammonium in slight excess. Allow to settle and filter, wash- 
 ing the precipitate with water containing a little ammonium sul- 
 phide. Keep the funnel covered with a watch glass during the 
 washing. When the precipitate and paper have been washed 
 four or five times and the paper is drained quite dry, pour on 
 the filter hot dilute hydrochloric acid, and allow the solution 
 to run into tho beaker in which the precipitate was made. 
 Wash with hot water. Now add a few drops of nitric acid and 
 evaporate to dryness in the beaker, dissolve in as little hydro- 
 chloric as is necessary to effect solution, dilute to about 25 c.c. 
 and filter. Wash paper with hot water. Precipitate the iron 
 with ammonia, boil, filter, wash, and ignite in the same man- 
 ner as described for the estimation of total iron and alumina.
 
 13 
 
 The weight equals ferric oxide (Fe 2 O 3 ) which deducted from 
 the total oxides of iron and alumina (Fe 2 O 3 +Al 2 O 3 ) leaves 
 the alumina (A1 2 O 3 ). 
 
 Following is the method by using permanganate of pot- 
 ash. Prepare a solution of permanganate by dissolving ^fr 
 grams of the c.p. salt in one litre of water. When all is in 
 solution pour it into a glass stoppered litre bottle and shake 
 thoroughly. (After its equivalent in iron is found it should 
 be labeled and kept in a dark place and its strength ascer- 
 tained from time to time). Standardize the solution by 
 means of ferrous sulphate (FeSO 4 7H 2 O). Take exactly 5 
 grams of the c.p. salt and dissolve in 300 c.c. water, add 
 10 c.c. sulphuric acid and cool by allowing the hydrant water 
 to run over the outside of the flask. Now fill a 50 c.c. bur- 
 ette (glass cock) with the permanganate solution exactly to 
 the mark and allow it to run into the ferrous sulphate solu- 
 tion, drop by drop, until a faint pink tint is obtained, which 
 shows that the iron is all oxidized and the one drop excess 
 of permanganate colors the solution. It is best to repeat the 
 operation several times and take an average. 
 
 Pure ferrous sulphate contains 20.1439 per cent of iron 
 (Fe) then .5 grams contains .1007 grams iron and if this 
 took 15 c.c. of the permanganate solution then I c.c. would 
 equal .0067 grama iron. With this solution we can now find the 
 amount of iron in an unknown solution. To do this the iron 
 must first be reduced to the ferrous condition by means of 
 metallic zinc or some other deoxidizer. To use zinc transfer 
 the solution of iron chloride obtained in the above fusion to a 
 flask of about 500 c.c. capacity and add 3 grams (roughly 
 weighed) of the granulated zinc, warm slightly, and allow the 
 action to go on until the solution is perfectly colorless. Then 
 add a few c.c. of hydrochloric acid to dissolve the remaining 
 bits of zinc and if the solution still remains colorless it may be 
 considered deoxidized. If not, more zinc must be added and the 
 action allowed to continue. When the solution is completely 
 deoxidized add a mixture of 10 c.c. sulphuric acid and 10 c.c. 
 water, wash off the funnel allowing the water to run down the 
 neck of flask and then cool by allowing the hydrant water to 
 run on the outside of the flask. Now run in the standard solu- 
 tion of permangate from the burette until the pink tint is ob-
 
 14 
 
 tained. The amount of permanganate solution used, less coi- 
 rection for zinc, is then read and knowing its strength in iron 
 the amount of iron in the sample is readily calculated. If we 
 found it required 5 4 c.c. standard permanganate solution with 
 a strength 1 c.c.=.0067 grams Fe., then 54 X. 0067 =.03618 grams 
 Fa, which multiplied by factor 1.428 gives .0517 Fe 2 O 3 . Hav- 
 ing now the weight of oxide of iron and alumina and oxide 
 of iron the difference equals alumina. 
 
 Calcium and Magnesium. Concentrate the filtrate and 
 decantation water from precipitation of the iron and aluminum 
 first adding a little hydrochloric acid, to about 100 c.c. and 
 proceed as detailed in the analysis of "Whiting" for the 
 estimation of calcium and magnesium. 
 
 Potassium and Sodium. The following method known 
 as the J. Lawrence Smith method will be found probably as 
 expeditious and accurate as any for the determination of the 
 alkaline salts. Weigh out 1 gram of the clay and rub up in a 
 mortar first with about a gram of c. p. ammonium choride 
 and then add 10 grams c. p. carbonate of calcium and mix 
 thoroughly. Transfer to a large platinum crucible, cover and 
 heat for a few moments to decompose the ammonium chloride. 
 Now place the crucible on the triangle and adjust the flame 
 so that the crucible is cherry red and keep at this tempera- 
 ture for about one hour. Remove flame and cool. Place 
 crucible with contents and cover in a beaker, add about 100 c.c. 
 of water and heat until the mass is thoroughly slaked. Take 
 out the crucible and wash with hot water, allowing water 
 to run back in beaker and filter. The filtrate contains the 
 alkalies with impurities. Add about 2 grams c.p. ammonium 
 carbonate and about 5 drops of ammonia and evaporate to 
 about 25 c.c. Filter off the calcium carbonate, wash slightly 
 with water. Add more ammonium carbonate to make sure 
 that all the calcium has been precipitated. If a precipitate 
 appears, evaporate to a small bulk and again filter. Usually 
 two or three treatments will take out all the calcium. Now 
 add a few drops of hydrochloric acid, evaporate to dry ness in 
 a weighed platinium dish, then heat carefully not quite to 
 redness until white fumes of ammonium chloride cease to 
 come off, cool and weigh as chlorides of sodium and potassium 
 (NaCl+KCl). Add a few c.c. of water to the dish and the
 
 15 
 
 chlorides should dissolve completely to a clear solution. If 
 any insoluble matter appears, it must be filtered off and the 
 filter washed once or twice with hot water and the filtrate again 
 brought to drynesa and weighed as before. If no insoluble 
 matter appears add a solution of platinic chloride in excess and 
 evaporate in a water bath until it begins to cake, then add 
 about 20 to 50 c.c; of 80 per cent, alcohol to dissolve the excess 
 of platinic chloride, stir and allow the crystals of potassium 
 platinic chloride to settle, filter in a previously dried and 
 weighed filter washing with 80 per cent, alcohol until the 
 washings come through colorless. Dry in oven at 110 0., 
 and weigh quickly. Weight equals the potassium platinic 
 chloride ( K 2 PtCl 6 ), multiply by factor .1939 gives K 2 O. Then 
 multiply K 2 PtCl 6 by factor .3055 which will give KC1. Deduct 
 this weight from the total KC1 and NaCl, difference equals 
 NaCl, which multiplied by the factor .5306 gives NaaO. 
 
 Water. To estimate the combined water ignite one gram 
 of the clay to redness in a platinum crucible until the weight 
 remains constant. The loss equals water. 
 
 The following analysis of China clays are given by 
 Hurst: 
 
 Cornwall. China. America. French. 
 
 Silica (SiOa) 46.78 50.50 47.13 48.37 
 
 Mumina (A1 2 O 3 ) 39.60 33.76 36.76 34.9o 
 
 Water (H 2 O) 13.16 11.22 15.13 12.62 
 
 Potash (K 2 O) 0.12 1.90 1.76 
 
 Ferric Oxide (Fe 2 O 3 )... 0.09 1.80 trace 
 
 Lime(CaO) 0.07 0.04 0.24 
 
 Magnesia (MgO) 0.80 
 
 99.82 99.98 99.06 97.94 
 
 4. Silica (Silex.) Silica is a natural product of the 
 composition SiO 2 , has quite an extended use as a pigment and 
 is used largely in the manufacture of wood fillers. It is 
 light, white, inert and insoluble in acids. Some of the brands 
 are made by pulverizing crystallized quartz (which is pure 
 silica) and others are found as powder of sufficient fineness 
 for use without any further preparation. As silica is found 
 in a pure condition an analysis is not often required. Occa- 
 sionally the relative purity of several brands may be desired 
 in which case the determination of silica alone will be suffi-
 
 - 16 - 
 
 cient Other constituents may be lime and magnesia, iron 
 and water, with possibly traces of alkalies. For the analysis 
 proceed as detailed in the analysis of China clay, page 10. 
 ANALYSES OF SILICA BY THE ATJTHOR. 
 
 No. 1 No. 2 No. 3 No. 4 
 
 Silica 99.40 97.70 98.01 98.14 
 
 Moisture 12 undet .32 
 
 Potassium Oxide . . . . undet undet .14 .24 
 
 99.52 97.70 98.15 98.70 
 
 5. Barium Sulphate (Baryies, Blanc Fixe.) Barium 
 sulphate is used largely as a cheapener in paints but its 
 analysis is not very often required. It consists of about 
 98 to 98.8 per cent, barium sulphate in the best grades, with 
 small amounts of calcium sulphate, silica or clay, iron and 
 alkaline salts. It is usually desired to ascertain only the 
 percentage of barium sulphate (BaSO 4 ) for which the fol- 
 lowing plan of analysis may be used: 
 
 Barium Sulphate. One gram of the dried sample is 
 mixied in a glass or agate mortar with seven grams sodium 
 carbonate and three grams potassium carbonate and then 
 fused over a blast lamp in a platinum crucible, and the 
 crucible and contents when cool, placed in a beaker and 
 covered with water. Now digest until the fused mass is 
 detached from the crucible and the barium carbonate that is 
 formed has settled. Filter and rub the crucible clean with a 
 rubber-tipped rod. Wash several times with hot water. 
 Dissolve the barium carbonate on the filter with warm hydro- 
 chloric acid (1 part acid, 3 parts water) placing a watch 
 crystal on top of funnel to prevent loss from effervesence. 
 Eepeat the acid treatment until all is dissolved, and thoroughly 
 wash the paper with hot water. The solution now contains 
 the barium as chloride. Heat to boiling, and while hot add 
 dilute sulphuric acid (1 part acid, 3 parts water) with con- 
 stant stirring until a precipitate ceases to form. Allow to 
 stand about four hours in a warm place, then filter, washing 
 the precipitate several times, first by decantation and then on 
 filter with hot water. It is best to use a double filter as the 
 precipitate has a great tendency to run through. Dry and 
 ignite, first separating the precipitate as clean as possible from
 
 17 
 
 the paper. Weight obtained multiplied by 100 gives the 
 percentage of barium sulphate. 
 
 Qualitative Tests for Barytes. To detect barium sul- 
 phate in a mixture of pigments, such as a mixed paint, dis- 
 solve about two grams in a mixture of 10 c. c. cone. c. p. 
 hydrochloric acid and 30 c. c. water and boil for five minutes. 
 Filter and wash the insoluble residue which may contain 
 barytes, with hot water. Dry the precipitate, separate from 
 paper and apply the following tests: Mix a small portion 
 with dry c. p. sodium carbonate on a piece of stick charcoal 
 (first digging out a round hole) moisten with water and 
 fuse with a blow-pipe. "When cool place the fused mass on 
 a bright silver coin, add a few drops of water and if barium 
 sulphate is present the coin will be blackened owing to the 
 formation of silver sulphide. If lead sulphate or calcium 
 sulphate were in the sample they will go into solution by the 
 treatment with hydrochloric acid. The insoluble residue 
 may be again confirmed by the flame test Bend the end of 
 a clear platinum wire into a email loop in which pick up 
 some of the material to be tested and moisten with dilute 
 hydrochloric acid. Now hold steadily in the outer edge of a 
 Bunsen burner flame until a sharp point of the material is 
 hot and if barytes is present a yellowish green tint will be 
 imparted to the flame. This test is a little difficult to make 
 at first as the tint appears in flashes, but with practice it will 
 be found very decisive. It is a good plan to try the flame 
 test, using pure barium sulphate. 
 
 In the presence of clay or silica the barytes may be in 
 such a small amount that the flame test or blow-pipe test 
 may not be decisive enough to pronounce the presence of 
 barytes with certainty. In such cases it is best to fuse about 
 one gram of the insoluble residue with sodium carbonate and 
 proceed as detailed above for the estimation of barytes, and if 
 it is desired to further confirm the precipitate obtained with 
 sulphuric acid, it may be done by the flame or fusion tests. 
 
 6. Magnesium Carbonate (Magnesite.) Insoluble Mat- 
 ter. Add about 20 c.c. water to one gram of the sample and 
 then about 10 c.c. cone, hydrochloric acid, cover until efferves- 
 cence ceases. Warm to complete the solution, allow to settle 
 and filter, washing the filter thoroughly with warm water.
 
 18 
 
 Dry, ignite paper and residue in platinum crucible. Weights 
 equals insoluble matter. 
 
 Oxide of Iron and Alumina. Add ammonia to the ni- 
 trate in slight excess, boil until the excess is driven off and 
 filter, washing with hot water. Dry, ignite and weigh oxide 
 of iron (Fe 2 O 3 ) and aluminum (A1 2 O 3 ). As the amount is 
 usually small, their separation is not required. 
 
 Calcium Carbonate. To the hot filtrate add ammonia to 
 quite strong alkaline reaction, and if a precipitate formed, 
 add ammonium chloride until dissolved. Now add solution 
 of ammonium oxalate until the precipitate ceases to form 
 and the ammonium oxalate is in excess. Let stand in warm 
 place for four hours and filter, wash and ignite as in whiting. 
 Multiply calcium sulphate (CaSO 4 ) by .7352 to convert to cal- 
 cium carbonate ( CaCO 3 ). If weighed as calcium oxide ( CaO ), 
 use factor 1.7857. 
 
 Magnesium Carbonate. Concentrate filtrate and wash- 
 ings to about 100 c.c., then add ammonia until the solution 
 smells strongly of it and cool by standing beaker in a basin 
 of cold water. When cold, add drop by drop with constant 
 stirring a cold clear solution of sodium phosphate in excess 
 and stir vigorously for several minutes, taking care that the 
 stirring rod does not touch the sides of the beaker. Stand 
 in a cool place over night. Filter off the supernatant clear 
 solution and wash the precitate several times by decantation, 
 using a mixture of 1 part ammonia and 2 parts water. 
 
 Then transfer precipitate to filter, cleaning the sides of 
 the beaker with a rubber tipped rod. Continue the washing 
 on the paper until a few c.c. of the filtrate, to vrlaich has been 
 added a drop of nitric acid, gives only a slight opalesence 
 with a solution of silver nitrate. Now proceed to dry and 
 ignite precipitate as directed in whiting, p. 9, calculating to 
 magnesium carbonate. 
 
 Pure magnesite consists of 52.4 per cent, carbonic acid 
 (CO 2 ) and 47.6 per cent, magnesia (MgO) and is rarely found 
 in such purity, but contaminated with iron alumina, lime and 
 moisture. 
 
 7. Hagnesium Silicate (Talc, Soapstone, Steatite.) 
 This material is a natural product containing about 60% 
 silica, 30% magnesium oxide and impurities, consisting of
 
 19 
 
 small amounts of water, iron, alumina, calcium, etc. Its 
 analysis is seldom required, but if desired the method given 
 on p. 11 for china clay may be used, bearing in mind that the 
 reagent, sodium phosphate, used in precipitating magnesium, 
 must be largely increased to insure the complete precipita- 
 tion. 
 
 To estimate the water, heat one gram in a porcelain 
 crucible, using a strong heat of a blast lamp as the water is 
 not expelled as readily as that in clay. Bepeat the heating 
 until the weight remains constant. 
 
 8. Zinc Oxide (Zinc White.) Zinc oxide is used to an 
 enormous extent at the present day as a pigment, and is found 
 in a majority of the mixed paints. Being an artifical product, 
 its composition varies and the price is governed by the per- 
 centage of oxide of zinc it contains, the best grades approxi- 
 mating 100 per cent, zinc oxide, while some of the cheaper 
 products contain more or less lead compounds, either as sul- 
 phates or oxides and possibly sulphate of zinc. The latter 
 element is considered harmful, as it is soluble in water and 
 is liable to cause the paint "streak." Zinc oxide is rarely 
 adulterated. 
 
 Insoluble Matter. For the analysis, take one gram of 
 the previously dried (in air oven at 100 C. ) sample and add 
 about 100 c.c. hot water, then 10 c.c. strong hydrochloric acid 
 and boil. The zinc oxide and sulphate of lead (also zinc 
 sulphate and lead oxide) will go into solution and any insoluble 
 matter such as sand or clay, as natural impurities, settle out. 
 Filter on small ashless filter and ignite as in whiting, page 7. 
 
 Lead. Add ammonia to the filtrate until nearly neutral, 
 but is still acid, then pass a rapid stream of hydrogen sul- 
 phide gas into the solution until it is saturated. Warm and 
 let stand until precipitate is settled. Filter and wash the 
 precipitate with water containing hydrogen sulphide, allow- 
 ing the wash water to run into the filtrate. The precipitate 
 will contain the lead as sulphide. (See note 2.) Dry in air 
 oven and ignite in a weighed porcelain crucible until the filter 
 paper is charred. Cool. Add a few drops of cone, nitric 
 acid to moisten, then add 5 c.c. fuming nitric acid and warm 
 until sulphur is expelled, then add about 5 c.c. dilute sul- 
 phuric acid (1 part acid, 3 parts water) and heat gently until
 
 20 
 
 nitric acid is driven off and white fumes of sulphuric acid 
 appear. Now place on triangle and heat gently until the acid 
 is entirely gone, then at a low red heat for a few moments, 
 cool and weigh as sulphate of lead (PbSO 4 .) 
 
 Zinc Oxide. Boil the filtrate from the lead precipitation 
 to expel sulphuretted hydrogen, add a little chloride of 
 ammonium, then ammonia to slight alkaline reaction, then 
 colorless or slightly yellow ammonium sulphide in slight 
 excess. Dilute to 250 or 300 c.c., cover and allow to stand in 
 a warm place until settled. Filter, Busing a good sized filter 
 paper and wash with water containing a little ammonium 
 sulphide. (The slimy precipitate of zinc sulphide has a 
 tendency to run through the paper. This may be greatly 
 obviated by first pouring on the filter a solution of ammonium 
 chloride. Jt is a good plan to change the beaker just before 
 adding the precipitate so that should it run through, time 
 will be saved from refiltering. ) It is best to wash by decan- 
 tation if the precipitate settles perfectly clear. When the 
 precipitate is all on the filter paper and the wash water runs 
 through, transfer the paper and contents to a small beaker 
 and cover the precipitate with dilute hydrochloric acid, stand 
 in a warm place until the smell of hydrogen sulphide, is gone, 
 then heat gently and filter, washing the filter with hot 
 water. The zinc is then precipitated as carbonate. Add dry 
 c.p. sodium carbonate from the end of a spatula (keeping 
 beaker covered with a watch glass during effervesence) until 
 the zinc is precipitated and the sodium carbonate is in excess. 
 Add about 250 c.c. hot water and boil vigorously for about 
 eight minutes, stirring occasionally to prevent bumping 
 which is liable to occur before the boiling point is reached. 
 The boiling renders the precipitate less flocculent and makes 
 it settle much more readily. When the precipitate of zinc 
 carbonate is thoroughly settled, pour off the clear supernatant 
 liquid, and add to the precipitate about 200 c.c. more of hot 
 water and stir vigorously. Allow to settle again and decant 
 as before. After several decantings, pour the precipitate on 
 a filter paper, and then rub the beaker clean with a rubber 
 tipped rod and wash with water until the filtrate shows no 
 alkaline reaction to test paper. The precipitate is then dried 
 in the air oven and removed as free as possible from the paper
 
 - 21 
 
 and placed on glazed paper. Ignite the paper in a weighed 
 porcelain crucible and cool. Now add the precipitate and 
 ignite gently at first and then at a red heat to constant weight. 
 The carbonate is converted by the heat to the oxide (ZnO) 
 and as such is weighed. 
 
 Sulphuric Add. One gram is dissolved in a mixture of 
 10 c.c. strong hydrochloric acid and 10 c.c. water and boiled 
 until solution is complete. Filter off any insoluble matter, 
 wash with hot water until all lead chloride crystals are dis- 
 solved. Keep solution hot, and add barium chloride until a 
 precipitate ceases to form and stand in a warm place to settle. 
 When completely settled, filter, keeping solution hot and 
 wash with hot water until a drop of the filtrate fails to give a 
 turbidity to a solution of silver nitrate. Ignite as in whiting 
 and convert to sulphuric acid (SO 3 ) by multiplying by .3433. 
 
 Calculation. Assuming that all the sulphuric acid will 
 combine first with the lead, multiply the sulphuric acid (SO 3 ) 
 found by 3.78 which gives lead sulphate. Deduct from total 
 lead sulphate and if any lead sulphate remains, calculate to 
 lead oxide (PbO) by multiplying by .7359. All the zinc then 
 remains as zinc oxide in which form it is weighed. If, how- 
 ever, there is not enough lead to combine with all the sul- 
 phuric acid the remaining sulphuric acid is calculated to sul- 
 phate of zinc (ZnSOi) by multiplying by 2.01. Calculate the 
 sulphate of zinc to zinc oxide by multiplying by .503 and de- 
 duct from total zinc oxide. The difference is the zinc oxide 
 in sample. 
 
 Note 1. Care must be taken that lead sulphate is not 
 mistaken for silica or clay, as it is not readily soluble in 
 hydrochloric acid. Hard boiling will generally dissolve it. 
 Should there be any doubt about the insoluble matter, pour 
 on the filter a warm solution of ammonium acetate, wash well 
 with hot water acidify the filtrate, then precipitate the lead 
 with sulphuretted hydrogen, and proceed as detailed for the 
 lead estimation. 
 
 Note 2. If. the precipitate is light colored it may be due 
 to some zinc having precipitated or possibly free sulphur, 
 due to the solution being too acid. In such cases the precip- 
 itate is filtered, washed from filter and boiled with a little 
 dilute nitric acid, filtered, washed with hot water and the lead
 
 - 22 - 
 
 again precipitated, after neutralizing the excess of acid with 
 ammonia. 
 
 Note 3. The sulphide of zinc, after drying, may be 
 placed in a weighed porcelain crucible and ignited for some 
 time at a red heat, allowing free access of air. The sulphide 
 is "roasted" or converted to the oxide at once. Care must be 
 taken to heat long enough to thoroughly convert it to the 
 oxide, and several weighings should be made to insure a con- 
 stant weight. This method is best when the zinc is present 
 in small amounts. 
 
 Remarks. In the majority of cases, it is generally de- 
 sired to obtain the percentages of zinc (as zinc oxide) and 
 total lead (as lead sulphate) not regarding the probable 
 small amounts of lead oxide or zinc sulphate. In the best 
 brands of zinc white, the two latter compounds need not be 
 seriously considered, in fact, the problem of forming com- 
 binations of sulphuric acid, lead and zinc to give oxide and 
 sulphate of zinc and oxide and sulphate of lead is a difficult 
 one. But there are on the market pigments consisting of 
 nearly equal parts of sulphate of lead and zinc oxide with 
 several percentages of lead oxide and zinc sulphate, being the 
 resulting product from roasting, volitilizing and condensing 
 lead and zinc ores consisting largely of sulphurets of these 
 metals. 
 
 As sulphate of zinc is soluble in water, a quick test might 
 be proposed by leaching it out and then estimating the zinc 
 in solution, but as zinc oxide is not absolutely insoluble in 
 water a large excess must be avoided. Take 5 grams and 
 brush into a filter and then fill the paper twice with warm 
 water, using about 20 c.c. for each washing. Allow all water 
 to drain and then precipitate the zinc in the filtrate with sul- 
 phuretted hydrogen after first making acid with acetic acid. 
 Proceed now as in the estimation of zinc by "roasting" 
 (note 3.) the sulphide to oxide and multiplying the zinc oxide 
 by 1.987 to obtain the sulphate of zinc, and this result is mul- 
 tiplied by 100 and divided by 5 to get the percentage. In 
 some instances, this method agrees very well with the long 
 method detailed in the first part, but its usefulness can best 
 be applied in a rough comparison when a number of samples 
 are tested for "soluble zinc compounds."
 
 23 
 
 Rapid Method for Analysis of Zinc Oxide. A method 
 that is more rapid than the tedious precipitation of zinc as 
 sulphide and quite accurate is the following: 
 
 Insoluble Matter. Dissolve one gram in 7 c.c. cone, 
 hydrochloric acid and about 10 c.c. water, boil for ten minutes. 
 After any insoluble matter is settled, filter and wash filter 
 with hot water. Dry, ignite and weigh insoluble matter. 
 
 Lead. To the filtrate cautiously add about 3 c.c. cone, 
 sulphuric acid, (or until lead ceases to precipitate) stir, evap- 
 orate to white sulphuric acid fumes. Cool. Add 10 to 20 c.c. 
 water, stir to dissolve the zinc sulphate and allow to stand 
 until the lead sulphate is completely settled. Then filter on 
 Gooch crucible wash first with water containing 2% sulphuric 
 acid then after removing the filtrate to a beaker rinsing out 
 the flask several times with water, finish the washing with a 
 mixture of half alcohol and half water. Dry, ignite and 
 weigh lead sulphate. 
 
 Zinc Oxide. To the filtrate in beaker containing the 
 zinc sulphate add sodium carbonate in excess, boil, filter and 
 wash with hot water, following the direction given on page 20 
 for estimating the zinc oxide. 
 
 Sulphuric Acid. For the sulphuric acid proceed as 
 directed on page 21. Having now the percentage of zinc, 
 lead and sulphuric acid the calculations are made as indi- 
 cated on page 21. 
 
 ANALYSIS. OF ZINC PIGMENTS BY THE AUTHOR. 
 
 Zinc Zinc Zinc 
 
 Zinc Oxide 
 
 White. 
 
 . 82.84 
 
 White 
 96.00 
 
 White 
 93.23 
 
 White 
 93.23 
 
 Lead Sulphate 
 
 15.57 
 
 3.57 
 
 4.81 
 
 4.81 
 
 
 1.60 
 
 
 
 
 Lead Oxide 
 
 
 
 
 1.96 
 
 
 
 
 
 
 
 100.01 
 
 99.57 
 
 98.04 
 
 100.00 
 
 "Leaded Zinc Zinc 
 
 Zinc." Lead Lead 
 
 ZincOxide 54.51 52.10 
 
 Lead Sulphate 34.56 40.51 41.03 
 
 ZincSulphate 1.16 5.12 
 
 Lead Ozide 
 
 96.18 98.85
 
 24 
 
 p. White Lead (Basic Carbonate of Lead. ) The actual 
 composition of white lead varies somewhat from that of theory, 
 and any material variance is supposed to affect its value as a 
 pigment 
 
 The theoretical composition is: 
 
 Lead Carbonate (PbCO 3 ) 68.95 per cent. 
 
 Lead Hydroxide (PbH 2 O 2 ) 31.05 " " 
 
 100.00 " " 
 or 
 
 Lead Monoxide (PbO) 86.32 per cent. 
 
 Carbonic Acid (CO 2 ) 11.36 " " 
 
 Water (H 2 O) 2.32 " " 
 
 100.00 " " 
 
 having, therefore, the formula 2PbCO 3 PbH 2 O3. The function 
 of the lead carbonate seems to be to impart body and color, 
 while that of the hydrate of lead is to form a chemical com- 
 bination with the oil to greatly increase the covering pro- 
 perties. 
 
 In the analysis of white lead the carbonic acid is the 
 usual constituent sought, and its determination is one requir- 
 ing care and exactness of apparatus. The usual method is to 
 calculate the carbonic acid to lead carbonate, substract from 
 100, and express the difference as lead hydrate. The reason 
 for this is that the estimation of the combined water requires 
 heat to drive it off and the liability of the sample to contain 
 carbonaceous compounds such as lead acetate, traces of oil, 
 etc. would give erroneous results. 
 
 In some laboratories, however, the combustion method is 
 used, as it gives quick and approximate results of sufficient 
 accuracy to check purchases and guard against adulterating 
 and for this reason the method is detailed on page 28. 
 
 If only the lead is desired, it may be obtained as follows: 
 
 Dissolve 1 gram in 5 c.c. nitric acid (1 42 sp. gr. ) and 20 c.c. 
 water and heat to solution. If any insoluble matter appears, 
 filter and wash with hot water. Now add dilute sulphuric acid 
 to filtrate, a few drops at a time, with constant stirring, until 
 the white precipitate of lead sulphate ceases to form, and 
 evaporate in hot plate to sulphuric acid fumes. Cool. Add 
 cautiously 15 c.c. water and an equal bulk of alcohol, stir
 
 25 
 
 thoroughly and allow to stand about an hour, or until super- 
 natant liquid is perfectly clear. Filter in a weighed Gooch 
 crucible. Wash with a mixture of one half water and 
 one half alcohol. After four or five washings, suck dry, 
 remove crucible, attach cap, and place on a hot plate for a 
 few moments to dry, then ignite on triangle at a red heat for 
 five minutes. Cool and weigh. Multiply weight of lead 
 sulphate by factor .7359 which converts it to (PbO) lead oxide. 
 
 If for any reason the Gooch crucible is not at hand or 
 inadmissable, and the lead sulphate must be filtered on paper, 
 proceed as detailed above and wash the paper, after adding 
 the precipitate, with the mixture of alcohol and water. Then 
 dry in oven, remove the lead sulphate from the paper as clean 
 as possible, placing in a large water glass, and ignite paper in 
 a weighed porcelain crucible. When all the carbon is burnt 
 off, cool the crucible, then add 3 or 4 c.c. water and about two 
 drops of nitric acid (sp. gr. 1.42), and warn until all the 
 metallic lead is in solution. Cool and add a few c.c. dilute 
 sulphuric acid to precipitate the dissolved lead then evaporate 
 on water bath until no more water or nitric acid fumes are given 
 off. This may be done more rapidly by placing in the warm 
 part of a hot plate but care must be observed that none of 
 the contents spirts out. Now place crucible in triangle and 
 heat by playing the flame gently, and when all the sulphuric 
 acid is expelled heat at a red heat for a few minutes, and cool. 
 Add the bulk of the precipitate and .again heat to redness for 
 about 5 minutes. Cool and weigh. 
 
 F. C. A. Meisel (School of Mines Quar. 1.04, Vol. XIV.) has given 
 the result of an investigation for the estimation of water and carbonic 
 acid in white leads by four methods: viz., Loss in ignition, loss by use of 
 alkalimeter, measuring carbonic acid gas by volume, and absorption of 
 carbonic acid in caustic potash solution, reaching the conclusion that 
 the last method gives the most trustworthy results, although it possibly 
 requires longer time. 
 
 Estimation of Carbonic Acid. The carbonic acid is 
 absorbed in the Liebig potash bulb A, which carries the 
 calcium chloride tube to prevent any moisture from being 
 absorbed from the aspirator. Connecting with the Liebig 
 bulbs are two U tubes, D, D, in which is freshly made 
 anhydrous sulphate of copper and pumice for the absorption 
 of any traces of hydrochloric acid gas and moisture. H is a
 
 26 
 
 boiling flask with a capacity of 150 c.c., fitted with a rubber 
 stopper with two holes in one of which passes the end of a 
 glass condenser and through the other passes the bent glass 
 tube of the bulb I. The latter has a glass stop cock at K. 
 J is a wash bottle containing solution of caustic potash. The 
 connection at L is made with a rubber stopper which fits 
 tightly into the bulb I. M. is a rubber tube connecting the 
 aspirator. 
 
 The caustic potash solution should h^ve a specific gravity 
 of about 1.27. This may be made by dissolving 30 grams of 
 the stick potash in 100 c.c. water, which will make a solution 
 of the desired strength. 
 
 The calcium chloride should be dried thoroughly at 
 200 c.c. (not fuzed); the white porous anhydrous chloride 
 thus produced being very deliquescent it should be kept in 
 glass stoppered bottle. The copper sulphate and pumice are 
 prepared by heating pieces of each, which should be about 
 the size of a pea, in a porcelain dish until the blue crystals 
 are white, then transferred to a glass- stoppered bottle for 
 keeping. 
 
 For the estimation of carbonic acid gas (CO 2 ), one gram 
 of the sample is carefully brushed into H and after the Lie- 
 big bulbs are weighed the apparatus is connected, the water 
 started in condenser E and the glass stop cock K in bulb I 
 closed. Pour in bulb tube I diluted hydrochloric acid made 
 up of 15 c.c. hydrochloric acid (12 sp. gr.) and 40 c.c. water. 
 Insert the rubber stopper L securely in bulb I and open the 
 stop cock K so that the acid will flow elowly in H. When 
 nearly all the acid has passed into flask H close stop cock and 
 apply a slow heat increasing gradually until the solution boils 
 which will take about 10 minutes. A few moments further 
 boiling will bring aJl the lead chloride in solution. When 
 this is accomplished the flame is lowered and suction com- 
 menced. After 10 minutes the flama is withdrawn and the 
 suction continued at the rate of about three bubbles per 
 second for about 20 minutes, at which time the apparatus 
 should be free from CO 2 . 
 
 Disconnect the potash bulbs and place in the balance 
 case for about 30 minutes to get the same temperature as that 
 of the case. At the end of this time if the levels of the
 
 27
 
 28 
 
 potash solutions are not the same remove the end caps to 
 equalize the pressure, then replace and weigh. The increase 
 in weight is the amount of CO 2 , which, multiplied by 100, 
 gives the percentage. This, multiplied by the factor 6.068, 
 gives the percentage of carbonate of lead and the difference 
 between this and 100 is expressed as hydrate of lead. 
 
 With due regard to the necessary precautions, the foregoing method 
 for the estimation of carbonic acid is accurate. The apparatus should 
 always be tested by running a blank, boiling the dilute hydrochloric 
 acid solution (but of course omitting the sample) for 10 minutes, and 
 aspirating about twenty minutes. The Liebig bulb should show no 
 appreciable increase in weight. 
 
 Combustion method for the determination of lead oxide, car- 
 bonic acid and water in dry basic carbonate of lead. 
 
 The method consists of heating the sample contained in a 
 platinum boat, in a short glass tube thus decomposing it into 
 water, carbonic acid gas and litharge (oxide of lead). The 
 litharge remains in the platinum boat, while the carbonic 
 acid gas is absorbed in a solution of caustic potash in a Lie- 
 big absorption bulb, and the water is taken up in a TJ tube 
 containing granulated calcium chloride. Having the weights 
 of litharge carbonic acid and water the several percentages 
 are calculated. 
 
 The apparatus is supported by the wooden stand. B is 
 a piece of heavy glass combustion tubing about six inches 
 long and sufficient diameter (f inch inside) to admit the 
 platinum boat A. At the right hand end is a rubber tube 
 which fits snugly to the calcium chloride tube C. On the 
 left hand side is inserted a rubber stopper, through which 
 passes a small glass tube to connect the guard tube Y which 
 is also filled with calcium chloride. 
 
 The platinum boat A is a small narrow box which must 
 hold one gram of the sample to be examined. C is the U 
 tube containing dried granulated calcium chloride to absorb 
 the moisture, and D is the Liebig potash bulbs containing a 
 solution of caustic potash in water, sp. gr. 1.2 for the absorp- 
 tion of carbonic acid gas. Z is another chloride of calcium 
 tube similar to C, but is not weighed and is a guard to pre- 
 vent any moisture getting back into D or C. As explained 
 before Y is a calcium chloride tube to dry the atmospheric air
 
 before entering the com- 
 bustion tube, and X is a 
 small bottle containing a 
 strong solution of potash 
 to free the air from car- 
 bonic acid. W is a rub- 
 ber tube connecting the 
 aspirator bottle to draw 
 air through the appara- 
 tus. All chloride of cal- 
 cium tubes should have a 
 plug of cotton at the ends 
 to prevent any of the chlo- 
 ride from being carried 
 out. 
 
 Detach C and D and 
 wipe carefully with dry 
 cloth. Both ends of each 
 should be carefully closed 
 by small pieces of solid 
 glass tubes inserted in the 
 pieces of rubber tubing. 
 Next weigh. Then weigh 
 the platinum boat and 
 in it weigh one gram of 
 the sample. Detach com- 
 bustion tube and gently 
 heat over a naked flame 
 until the tube is hot, then 
 suck the air through by 
 the mouth this being 
 necessary to remove any 
 moisture. Now connect 
 the whole apparatus in 
 the position as seen in the 
 cut. Draw air through 
 by means of the aspirator 
 bottles at the rate of a 
 few bubbles per second. 
 Note whether there are
 
 - 30- 
 
 any leaks, and if there are none, heat with the alcohol lamp 
 slowly along the bottom of the tube until the whole tube is 
 hot Place the lamp underneath boat and heat for about 20 
 minutes or until the lead has changed from white to the 
 red color of litharge. When it is of uniform color remove 
 the lamp and allow air to aspirate for about 10 minutes. 
 Disconnect the calcium chloride tube C, plug the ends as 
 before the operation, and do the same with the potash bulbs 
 D and weigh. Observe precautions on p. 26, for weighing 
 the bulbs. The increase of weight equals the amounts of 
 carbonic acid and water. When these are weighed the boat 
 containing litharge will be cool enough to weigh. The 
 difference between the weight of the boat plus litharge and 
 the weight of boat equals the weight of litharge. We now 
 have the following weights: Litharge (PbO), water (H 2 O), 
 carbonic acid gas (CO 2 ).
 
 31 
 
 Qualitative Tests of White or Tinted Mixed Paints, Paste 
 Paints, Fillers, Etc. 
 
 The readiness of lead sulphate and calcium carbonate to 
 react, when the latter is in excess, in treatment with dilute 
 acetic acid precludes the use of acetic acid as a general sol- 
 vent for mixtures of pigments. 
 
 When the above mentioned pigments are so treated, lead 
 carbonate and calcium sulphate are formed and both go into 
 solution and part if not all of the lead existing as sulphate 
 will be figured with the soluble lead pigments such as lead 
 oxide or carbonate. 
 
 Acetic acid may be used, however, when either one of 
 them only is present and although lead sulphate is slightly 
 soluble the result will be accurate enough (especially enough 
 when sulphuric acid is also estimated) for the purposes for 
 which an analysis of a mixtures of pigments is used. 
 
 As there are on the market, and in large use, pigments 
 that contain considerable lead sulphate such as "sublimed 
 lead," "leaded zinc," "zinc lead," "zinc oxide," it is obvious 
 that acetic acid as a solvent cannot be used to advantage 
 except in the mixtures in which lead sulphate and calcium 
 pigments are present either singly or not at all. 
 
 For this reason it will be necessary to vary the method 
 employed in accordance with preliminary tests. 
 
 Of course the regular methods of analysis may be used in a mixture 
 of pigments by estimating the acid radicals and bases, but the time in- 
 volved is much longer and the tedious separation of lead and zinc by the 
 use of sulphuretted hydrogen and ammonium sulphide in mineral acid 
 solution is avoided. Then, too, the combinations to arrive at the differ- 
 ent pigments used is often a matter of conjecture. In the foregoing the 
 combinations are much more rapidly obtained particularly in scheme I.
 
 CHAPTER III. 
 
 WHITE AND TINTED PAINTS. 
 
 Qualitative Analysis of White or Tinted Paints, Paste 
 Paints, Fillers and Enamel Paints. 
 
 Boil about one gram of the extracted sample with from 
 25 c.c. to 50 c.c. of acid ammonium acetate (see note 1) for 15 
 minutes. Filter and wash with hot water. Note whether 
 effervescence takes place, indicating carbonates. 
 KESIDUE. 
 
 Ignite residue in a porcelain crucible. When cool test portion 
 by flame test for barytes. If siiica or China clay is suspected mix 
 residue with five or six times its weight of sodium carbonate in a 
 platinum crucible. Fuse. When cool place crucible and contents in 
 beaker and coyer the crucible with water and boil until the mass is dis- 
 integrated. Filter. Dissolve the barium carbonate on filter in few c.c. 
 hydrochloric acid and allow to run in another beaker. Then add 
 sulphuric acid in slight excess which will throw down any barium as 
 barium sulphate. See Note 1. 
 
 To the nitrate from the barium carbonate and barium sulphate add 
 hydrochloric acid in slight excess, place in a platinum dish and boil 
 rapidly to dryness on a hot plate or directly over a low Bunsen burner 
 flame. Heat until hydrochloric and sulphuric acids are gone and cool. 
 Moisten with hydrochloric acid, add about 25 c.c. water and warm to 
 dissolve. Any insoluble residue is silica. Filter, and to filtrate add 
 ammonia in slight excess and boil. A precipitate of aluminum hydrate 
 together with the presence of silica indicates China clay. Now add 
 ammonium oxalate, stand a short time and, if calcium oxalate is preci- 
 pitated, filter. Cool filtrate add ammonia and sodium phosphate, and if 
 a precipitate of ammonium-magnesium-phosphate appears after standing 
 a few hours it indicates presence of magnesiiim silicate. See Note 2.
 
 33 
 
 FlLTEATE. 
 
 Divide the filtrate in three nearly equal parts and pro- 
 ceed in each as follows: 
 
 Test for sulphates 
 
 Add a few c.c. cone. 
 
 Ammonia is added 
 
 by adding a few drops 
 of hydrochloric acid, 
 heat to boiling, then 
 add a few c.c. of bari- 
 
 sulphuric acid or until 
 the addition of a few 
 drops ceases to form a 
 precipitate of lead sul- 
 
 in excess, then ammo- 
 nium sulphide until a 
 precipitate ceases to 
 form. Warm and stir 
 
 um chloride. A pre- 
 
 phate. Filter. To the 
 
 to collect precipitate. 
 
 cipitate of barium sul- 
 
 filtrate add ammonia 
 
 Filter. To the warm 
 
 phate indicates pre- 
 
 in excess, then a few 
 
 filtrate add ammonium 
 
 sence of lead sulphate 
 or possibly calcium 
 sulphate. 
 
 c. c. ammonium sul- 
 phide. A white pre- 
 cipitate indicates pre- 
 
 oxalate in excess, heat 
 to boiling point and 
 filter off calcium ox- 
 
 See Note 3. 
 
 sence of zinc oxide. 
 
 alate indicating pre- 
 
 
 See Note 4. 
 
 sence of calcium car- 
 
 
 
 bonate or calcium sul- 
 
 
 
 phate. Cool the fil- 
 
 
 
 trate and add solution 
 
 
 
 of sodium phosphate, 
 
 
 
 stir and stand in a cool 
 
 
 
 place for about thirty 
 
 
 
 minutes and if any 
 
 
 
 magnesium is present 
 
 
 
 a precipitate will form 
 
 
 
 indicating magnesium 
 
 
 
 carbonate. 
 
 
 
 See Note 5. 
 
 Note 1. Acid ammonium acetate solution may be pre- 
 pared by mixing 15 parts water with 30 parts ammonia (sp. 
 gr. 0.90) to which is added 50 parts glacial acetic acid. Test 
 the solution with barium chloride, which should give no trace 
 of a precipitate. About 70 c.c. of this solution will dissolve 
 one gram of lead sulphate in boiling ten to fifteen minutes. ^ 
 
 Note 2. If any silica, other than that in the clay, is 
 suspected it will be necessary to make a quantitative analysis 
 in order to determine its percentage. 
 
 Note 3. Calcium sulphate (gypsum) is used in paints 
 to some extent and its presence complicates an analysis when 
 whiting or lead compounds are present. It cannot be de- 
 tected by dissolving the gypsum in water as might at first 
 be supposed, owing to the reaction that takes place between 
 sulphates and carbonates of lead and calcium. The fact of 
 this peculiar reaction is brought out by G. W. Thompson in
 
 34 
 
 the "Journal of the Society of Chemical Industry, Nov. 80, 
 1896," and the method here used for determining mixtures of 
 sulphates and carbonates of lead and lime pigments by nitric 
 acid and alcohol is based on the method given there. To 
 test for the presence of gypsum proceed as follows: To 
 about 1 gram add 20 c.c. of a mixture of 9 parts alcohol (95% } 
 and 1 part nitric acid (1.42 sp. gr.) and after stirring allow to 
 stand about 20 minutes. Then decant on a filter and again 
 treat with the nitric acid-alcohol mixture, allowing to stand and 
 decant as before. Repeat the treatment four times then pour 
 any residue on filter and wash residue with nitric acid-alcohol 
 mixture. If gypsum was present it will remain undissolved, 
 while only the calcium carbonate (with possibly some of the 
 zinc and lead salts) will go into solution. Now wash the 
 residue of gypsum and other insoluble matter into a beaker 
 with the aid of a wash bottle, add a few c.c. hydrochloric acid, 
 boil and filter. To the filtrate add ammonia in slight excess, 
 then ammonium sulphide, and warm until precipitate is set- 
 tled. Filter. To the warm filtrate add ammonium oxalate 
 and warm a few moments. A white precipitate of calcium 
 oxalate indicates the presence of calcium which existed as 
 sulphate. 
 
 Note 4. If lead is present it may be as the basic 
 carbonate, lead sulphate or lead oxide. Only a complete 
 quantitative analysis will distinguish in which form the lead 
 may be. 
 
 Note 5. If only traces of magnesium carbonate are 
 found they are probably due to impurities in the whiting. It 
 is sometimes used in woodfillers. 
 
 Note 6. Zinc sulphite and lead sulphite are seldom if 
 ever found in American paints and for this reason have not 
 been considered herein.
 
 35 
 
 Having now the qualitative tests the scheme to use is 
 determined by the following conditions: 
 
 USE SCHEME I. 
 
 If sulphates are present but no calcium pigments. 
 (Indicating sulphate of lead and absence of calcium car- 
 bonate or calcium sulphate.) 
 
 Or, if calcium pigments are present but no sulphates. 
 
 (Indicating calcium carbonate and absence of calcium 
 
 sulphate and lead sulphate.) 
 
 USE SCHEME II. 
 
 "When sulphates and calcium pigments are present. 
 
 NOTE. The above does not include the insoluble pigment, barytea.
 
 36 
 
 A Gooch crucible is quite indispensable for the rapid filtering and 
 ignition of precipitates, and is particularly useful in igniting precipitates 
 that are liable to be reduced by filter paper, such as lead sulphate. The 
 asbestos of the silky, fibrous kind should be previously digested for 
 several hours in dilute hydrochloric acid, then washed by decantation 
 with distilled water until free from acid, and thrown on a filter to drain 
 and dry, then kept in a wide mouth bottle. To prepare the asbestos pad 
 in the Gooch crucible, mix several grams (or a good sized "pinch") in a 
 small beaker with distilled water and pour in crucible applying gentle 
 suction. When quite dry by means of the finger press down the edge of 
 the asbestos so that the whole pad has an even surface and is about an 
 eighth of an inch in thickness. Now apply pressure until quite free 
 from water, remove from funnel, attach the platinum cap and place on 
 hot plate to dry, then place on triangle and ignite for about five minutes 
 over flame at red heat. Cool, remove cap and weigh. 
 
 If for any reason the Gooch crucible is not admissible and it is de- 
 sired to use a paper filter in preference to the asbestos pad, a perforated 
 platinum cone may be used to prevent the paper being broken by the 
 pressure of the pump. A funnel should be selected that the cone 
 exactly fits so that the paper will not be broken from the sharp edge. 
 Fold the paper and place in funnel, then fill the funnel with water and 
 apply the suction. The paper will then be drawn tightly to the cone 
 and funnel and is ready for use. The use of filter pumps to facilitate 
 filtering operations has now become quite general and in most labora- 
 tories are indispensable. The kind of pump is generally determined by 
 the water supply. The Richards injector is generally used where the 
 water supply is sufficient. A very serviceable and simple pump may be 
 arranged by using aspirater bottles as shown in cut on p. 37. The aspi- 
 rate r bottles A and B connect by B eans of a rubber tube with C which is 
 an empty guard flask. It is necessary that the fall of water between A and 
 B should be a considerable distance, about seven feet being generally 
 sufficient. On the tube connecting A and B is a clamp for regulating 
 the flow. The guard flask C is connected by another rubber tube with 
 flask E. In the neck of E is a funnel for holding either the platinum 
 cone or crucible. The water flowing from A to B causes a partial 
 vacuum and creates a pressure on the filter. As soon as the water has 
 run from A to B they are quickly reversed and the flow resumed, the 
 same water being used over again. It is obvious that for filtering corro- 
 sive liquids such as nitric acid, this method cannot be used to advan- 
 tage, but for lead sulphate in sulphuric acid or zinc carbonate, etc., it 
 will be found very serviceable.
 
 37 
 
 28S46Q
 
 38 
 
 2. SCHEME I. 
 
 Boil one gram of the sample in 5 c.c. glacial acetic acid 
 and about 25 c.c. of water for 10 minutes. Wash down the 
 sides of the beaker with water, then dilute to about 50 c.c. 
 and stand until settled. Filter on a 9 c.m. filter. 
 EESIDUE. 
 
 The residue insoluble in acetic acid may consist of either lead sul- 
 phate, china clay, barium sulphate, silica or magnesium silicate. 
 
 In order to effect a decomposition and solution it will be necessary 
 to fuse in a platinum crucible which is impracticable when lead sulphate 
 is present. To remove the lead sulphate either one of two methods may 
 
 1. By converting to lead carbonate and dissolving in dilute acid p. 39. 
 2. Dissolving at once in hot ammonium acetate p. 39. 
 In either case the insoluble clay, silica, barytes, magnesium silicate 
 will remain to be treated as directed on p. 40. 
 
 FILTRATE. 
 
 Lead acetate Pb (CaHsO^, Zinc acetate Zn (C 2 H3O 2 )2, Calcium acet- 
 ate Ca (C-sHsOj^, Magnesium acetate Mg (C 2 H 3 O 2 )2. 
 
 Pass a rapid stream of sulphuretted hydrogen gas until saturated, 
 warm and allow the precipitates of lead and zinc sulphides to settle 
 quite well. Filter on a double filter using a platinum cone and pump, 
 and when the supernatant liquid is filtered add about 20 c.c. sul- 
 phuretted hydrogen water. Stir and again allow the bulk of the precip- 
 itate to settle. Filter and repeat the washing by decantation four times. 
 Now run the precipitate on the paper and by the aid of the wash bottle 
 containing sulphuretted hydrogen spirt any loose precipitate on the 
 filter disregarding what adheres to the beaker. Wash once or twice on 
 filter with sulphuretted hydrogen water and Buck quite dry. 
 
 PRECIPITATE. 
 
 Lead sulphide (PbS), Zinc sul- 
 phide (ZnS), p. 41. 
 
 FILTRATE. 
 
 Calcium acetate, Ca 
 Magnesium acetate, Mg (C 2 H 3 O 2 )2, 
 p. 42.
 
 - 39 
 
 REMOVING LEAD SULPHATE FROM EESIDUE INSOLUBLE 
 IN ACETIC ACID. 
 
 Method II. By Ammon- 
 ium Acetate : Remove filter 
 and contents from funnel, 
 place in a beaker and add 
 from 30 c.c. to 50 c.c. acid 
 ammoninm acetate solution, 
 (see note I.) and boil for 10 
 minutes. Then filter any 
 insoluble residue (contain- 
 ing first filter paper) and 
 wash thoroughly with hot 
 water. The lead will now be 
 in the filtrate. The residue 
 is treated as described on 
 p. 40. 
 
 Method I. By Ammonium Carbon- 
 ate : Plug up the end of the funnel with 
 a filter paper tightly rolled or a better 
 plan is to slip on the end a piece of rub- 
 ber tubing about an inch long and close 
 up the other end of the rubber tube with 
 a bit of solid glass rod. Now place on the 
 filter two or three grams of ammonium 
 carbonate and fill the filter with warm 
 water within a half inch of the top. 
 Cover with a watch glass and allow to 
 stand in a warm place for six to ten 
 hours best over night. The lead sul- 
 phate is by this means converted to lead 
 carbonate. Now pull off the rubber plug 
 and wash the filter with warm water. 
 Reject filtrate. Dissolve the lead car- 
 bonate by pouring warm acetic acid on 
 filter quickly covering with watch glass 
 to prevent loss by effervescence. Wash 
 off watch crystal, allowing the water to 
 run on the filter and then wash out the 
 lead acetate with hot water. It is a good 
 plan to add acetic acid a second time to 
 make sure that all the lead carbonate is 
 dissolved. Proceed with the residue as 
 described on p. 40. 
 
 Determination of Lead in Solution obtained by either 
 Method I or II. Pass a stream of sulphuretted hydrogen 
 gas through the solution until saturated and filter. Reserve 
 filtrate. If there is considerable lead sulphide proceed ex- 
 actly as described on p. 24 for the estimation of lead as sul- 
 phate, using a Gooch crucible. The lead is weighed as sul- 
 phate (PbSO 4 ) and exists as such in the sample. Should the 
 precipitate of lead sulphide be small it may be converted 
 directly to the sulphate as follows: Dry precipitate in an 
 air oven and carefully transfer from the paper to a piece of 
 glazed paper or watch glass. Now fold the paper and place in 
 a weighed porcelain crucible and ignite until charred. Add 
 the precipitate and moisten all with nitric acid (1.42 sp. gr.) 
 Heat gently until the carbon is consumed, cool and add about 
 5 c.c. fuming nitric acid, cover with small watch crystal and
 
 40 
 
 heat until the free sulphur is oxidized. Then add a drop or 
 two of sulphuric acid and heat as usual, finally cooling and 
 weighing the lead sulphate. 
 
 Filtrate. The filtrate from the lead sulphide precipitate 
 is boiled to expel sulphuretted hydrogen, then ammonia 
 added in slight excess and ammonium oxalate. If a precipi- 
 tate appears it is probably due to calcium carbonate in the 
 china clay or possibly whiting that failed to dissolve in the 
 acetic acid. If the sample contains whiting, that found in the 
 insoluble residue is added to it but if no appreciable amount 
 is present it is added to the china clay or if desired it reported 
 singly. China clay or silica of good quality does not contain 
 calcium soluble in acetic acid. 
 
 Residue Insoluble in Acetic Acid After Removing Lead 
 Sulphate. Dry the residue left after removing the lead sul- 
 phate, clean precipitate as free as possible from the paper, 
 ignite paper in a weighed porcelain crucible, cool, add preci- 
 pitate and heat to redness for ten minutes. Weight equals 
 barytes, silica or china clay. Transfer to a capacious plat- 
 inum crucible, add ten times its weight of sodium carbonate, 
 fuse and proceed as directed in china clay p. 11. After the 
 mass is thoroughly disintegrated, filter off the insoluble bar- 
 ium carbonate, wash with hot water (reserving filtrate) and 
 dissolve on filter with dilute hydrochloric acid. Finally pre- 
 cipitate with sulphuric acid as directed on p. 16, which is the 
 barium sulphate existing as such in the sample. 
 
 If the barium sulphate be deducted from the total insol- 
 uble matter the difference is the china clay and silica. If, 
 however, a more accurate result is desired unite the filtrates 
 from the barium carbonate and barium sulphate precipita- 
 tions transfer to a platinum dish evaporate to dryness first on 
 a water bath and finishing on a hot plate. Heat until no more 
 sulphuric acid fumes are given off. Cool. Add sufficient 
 water and heat in water bath until all is in solution except the 
 silica, then add a drop or two of sulphuric acid and again 
 bring to dryness and heat until all acid fumes are driven off. 
 Now add water and proceed as directed in china clay p. 11. 
 for the estimation of silica and alumina. The average com- 
 position of china clay is 2 SiO 2 , A1 2 O 3 2 H 2 O containing 39.53 
 per cent, of A1 2 O 3 . Multiply the A1 2 O 3 found by 2.537 and
 
 41 
 
 the result will be china clay. Then multiply the china clay 
 found by factor .465 and the result will be the silica in the 
 china clay and if the difference exceeds 5 per cent, it may be 
 due to free or added silica. 
 
 If the qualitative examination shows magnesium present in the in- 
 soluble residue then it will be necessary to proceed with the filtrate after 
 filtering off the aluminum. This is done exactly as detailed in china 
 clays for the estimation of calcium and magnesium. When such com- 
 plex insoluble residues are found and this is rarely the case, it is a 
 difficult problem to form an opinion or give percentage of the original 
 products. In such cases it is the better plan to give the percentage 
 found such as silica, aluminum oxide, magnesium oxide, barytes, etc., 
 with possibly an attempt to combine the percentages to give probabl* 
 products, which may ba free silica, barytes, china clay, magnesium, 
 silicate, etc. 
 
 Precipitate of Lead Sulphide and Zinc Sulphide. 
 Remove the filter and contents from the funnel and spread 
 out on a glass plate or the concave side of a large watch glass. 
 Now with a wash bottle containing hot water spirt the pre- 
 cepitate from the paper into the beaker in which the precipi- 
 tation was made. Add moderately strong hot nitric acid to 
 the paper which dissolves the remaining stains of the sulphide 
 and allow to run in beaker. Finally, wash the paper with 
 hot water until it has no acid reaction. (The paper is now 
 rejected. ) Boil until all is in solution and only the light 
 colored sulphur remains. If the precipitate is dark colored, 
 due to undissolved lead sulphide, add a few c.c. of cone, nitric 
 acid and again boil which will usually dissolve the last traces 
 of the sulphides. Now filter and wash the sulphur until free 
 from acid and if filtrate exceeds 50 C.G., boil to about that 
 volume and cool. 
 
 Precipitate lead by adding cautiously 5 c.c. cone, sul- 
 phuric acid and evaporate as rapidly as possible without 
 bumping. When the dense white fumes of sulphuric acid 
 appear, allow to cool. Add 25 c.c. water, stir to dissolve all 
 zinc sulphate, then stand until perfectly clear and the lead 
 sulphate is settled. Filter in a Gooch crucible, wash with 2% 
 solution of sulphuric acid and water, until all sulphate of zinc 
 is washed out, then remove filtrate and finish the washing 
 with a mixture of half alcohol and half water, proceeding as 
 directed on p. 24 for the estimation of lead. Multiply the
 
 42 
 
 lead sulphate by .852 to convert to 2PbCO 3 PbH 2 O 2 . (Basic 
 carbonate of lead. ) 
 
 Dilute filtrate to about 400 c.c., heat nearly to boiling, 
 then proceed with the estimation of zinc by precipitating 
 with sodium carbonate, finally igniting and weighing as zinc 
 oxide (Zn O) which exists as such in the sample. Follow 
 directions for estimation of zinc on p. 20. 
 
 Filtrate Containing Calcium Acetate and Magnesium 
 Acetate. Transfer the nitrate to a beaker and rinse out the 
 flask which contained it several times with water, adding the 
 washings to the beaker, and boil down to about 75 c.c. If 
 sulphuretted hydrogen is not entirely disappeared, continue 
 boiling until but a very faint odor is perceptible. Now add 
 ammonia in excess and to the hot solution add, drop by drop, 
 with constant stirring, solution of ammonium oxalate, and 
 allow to stand on the edge of the hot plate for about four 
 hours. Filter the calcium oxalate, washing with hot water, 
 dry, ignite and weigh as calcium sulphate, calculating to cat- 
 cium_carbonate (CaCO 3 ) as directed on p. 8. 
 
 If magneaiom is present, evaporate the filtrate to about 
 50 c.c., cool and proceed as directed on p. 9, for the estima- 
 tion of magnesium. Weight of magnesium pyrophosphate 
 (Mg 2 P 2 O 7 ) obtained is calculated to magnesium carbonate 
 (MgCO 2 ) by multiplying by .7567. 
 
 Note. If barium carbonate is present it will be necessary to first 
 separate it from the calcium and magnesium by adding dilute sulphuric 
 acid drop by drop until a precipitate ceases to form, allow to stand in a 
 warm place until the precipitate is pretty well settled, then filter and 
 proceed as in barytes for the washing ignition and weighing of the 
 barium sulphate (BaSOi). Multiply by .845 to convert to barium car- 
 bonate (BaCOs). It 13 essential that the solution be kept quite dilute 
 and a few c c. hydrochloric acid added to prevent any calcium if present 
 from precipitating as sulphate. 
 
 Notes on Scheme I. 
 
 Note I. Owing to the probable presence of "sublimed 
 lead" or products containing lead oxide, it will be necessary, 
 where it is suspected, to make an estimation of the carbonic 
 acid present, which may be done by the apparatus and 
 method described on p. 25. Then having the carbonic acid 
 (CO 2 ) calculate it to basic lead carbonate by multiplying 
 by 8.8. Convert the basic carbonate of lead found to lead
 
 43 
 
 sulphate and deduct from the total lead sulphate (acetic 
 acid solution), and if there is any excess of lead sulphate 
 (say one per cent.) it is calculated to lead oxide (PbO). 
 Should whiting be present it will be necessary to first satisfy 
 it with carbonic acid by multiplying the calcium sulphate 
 (CaSO 4 ) found by .735 (of if CaO by 1.885) which equals 
 whiting (CaCO 3 ). Now find the carbonic acid (CO 2 ) in the 
 whiting by multiplying by .44, and deduct from the total car- 
 bonic acid found. If magnesium carbonate is present, cal- 
 culate its carbonic acid by multiplying by .52 and deduct from 
 the CO 2 left Then calculate the balance of the CO 2 to basic 
 carbonate of lead by factor 8.8. Any lead left unsatisfied is 
 calculated to lead oxide (PbO) by deducting the lead in the 
 white lead from the total lead found soluble in acetic acid. 
 
 Note II. If the sample be a tinted paint, the coloring 
 or tinting pigment is usually found by difference, that is, the 
 total result by analysis is subtracted from 100. In tinted or 
 mixed paints it does not exceed but a few per cent, and the 
 pigment used in coloring is disregarded. 
 
 Note III. If the sample consists of only white lead and 
 zinc oxide, dissolve in acetic acid as usual, filter, and instead 
 of precipitating as sulphides the lead may be separated at 
 once by adding sulphuric acid and evaporating as usual, and 
 then precipitating the zinc in the filtrate. The lead sulphate 
 if present will remain insoluble in the filter and is treated in 
 the usual way. As lead sulphate is not absolutely insoluble 
 in acetic acid particularly when it is present in large amounts, 
 it is well to make a determination of the sulphuric acid and 
 calculate to (PbSO 4 ) lead sulphate, then deduct from the total 
 lead sulphate (both soluble and insoluble in acetic acid) and 
 the balance is calculated to white lead. 
 
 Note IV. In the analysis of complicated mixtures of 
 pigments the chemist has to assume some arbitrary formulae 
 such as that of white lead which do not always conform to 
 the theoretical formula, but are liable to vary somewhat. So, 
 too, in the estimation of china clay. Yet there is no ready 
 method that will give these in their exact composition and 
 neither is it necessary in the analysis of a paint for practical 
 purposes.
 
 44 
 
 3. SCHEME II. 
 
 For mixtures containing sulphates or carbonates of lead 
 and calcium together with other pigments. 
 
 Carbonic Acid. If carbonic acid is present it is esti- 
 mated by the method and apparatus as described on p. 25. 
 
 Sulphuric Acid. Determine as detailed on p. 21, weigh- 
 ing as barium sulphate, convert to 8O 3 by factor .3433. 
 
 Bases. Boil one gram 20 minutes with about 40 c.c. acid 
 ammonium acetate sol ution, keeping the beaker covered. Filter 
 and wash filter thoroughly with hot water. 
 
 INSOLUBLE. 
 
 Barytes, china clay, silica and 
 magnesium silicate. Dry, ignite 
 and weigh, then proceed as detail- 
 ed for the separation and estima- 
 
 FlI/TRATE. 
 
 Lead, zinc, calcium and magne- 
 sium acetates. Proceed as detailed 
 for their separation and estimation. 
 Pages 41 and 42. 
 
 tion of silica, aluminum, barium, 
 calcium and magnesium, p. 40. 
 
 Notes on Scheme II. . 
 
 Note I. If the qualitative test shows that lime exists 
 both as the carbonate and sulphate together with lead sul- 
 phate (and the latter is generally present in mixed paints), 
 it will be necessary to extract and estimate the lime car- 
 bonate, and having the total lime, that existing as sulphate 
 may be calculated. The following method due to Thompson 
 is probably the best. 
 
 Proceed as follows: One gram of the sample is treated 
 in a small beaker with 25 c.c. of a mixture of 1 part nitric 
 acid (1.4) and 9 parts 95 % alcohol, and allowed to stand without 
 heating for 20 minutes. Then decant the clear liquid on a 
 dry filter and again treat with the alcohol-nitric acid mixture, 
 allow to stand and filter as before, repeating the operation 
 four times. Finally wash the paper with the mixture. The 
 calcium carbonate together with some lead and zinc will go 
 into solution, while any gypsum and insoluble matter will 
 remain on filter and is disregarded. Now evaporate the fil- 
 trate to dryness to expel alcohol, and add sulphuric acid and 
 heat to fumes. Cool. Add a few c.c. nitric acid, then am- 
 monia to alkaline reaction, then acetic acid in excess, and boil 
 to solution. While hot pass sulphuretted hydrogen gas until
 
 45 
 
 saturated and filter off any lead or zinc. Wash precipitate, 
 first by decantation, then on filter with water containing 
 hydrogen sulphide, and evaporate filtrate and washings until 
 sulphuretted hydrogen has dissappeared. Meke alkaline 
 with ammonia if not already so, precipitate the calcium wit? 
 ammonium oxalate, allow to stand several hours in a warm 
 place, filter, wash, ignite and weigh as calcium sulphate. 
 
 Note II. As basic carbonate of lead does not conform 
 strictly to the theoretical formula any excess of lead after 
 satisfying the carbonic acid and sulphuric acid does not nec- 
 cessarily imply the presence of lead oxide. The latter is 
 usually present in sublimed products or in the presence of 
 much lead sulphate, It is possible that a very small percent- 
 age of lead in the drier may not have been completely washed 
 out with the gasoline or ether, but this is the exception 
 rather than the rule. 
 
 Note III. Mention is made of the presence of barium 
 carbonate but it is little used in American paints. Should it 
 be found with soluble sulphates a decomposition will take 
 place on treatment with acid forming insoluble barium sul- 
 phate and complicating !he analysis. Only a very complete 
 analysis of the bases and acid radicals would give sufficient 
 data to form the probable combinations. 
 
 A paste paint has recently been introduced containing 
 about 10 per cent, barytes (blanc fixe) and 90 per cent, barium 
 carbonate. The analysis of such a mixture is easily made by 
 dissolving in dilute hydrochloric acid, filtering and washing 
 with hot water. The residue after ignition and weighing 
 represents the barium sulphate. To the filtrate dilute sul- 
 phuric acid is added in slight excess and the barium sulphate 
 obtained in the usual way is calculated to barium carbonate 
 by the factor .845. 
 
 Note IV. Consult notes I, II and III in Scheme I. 
 
 CALCULATIONS. 
 
 When Gypsum is Absent If no gypsum is present, cal- 
 culate the sulphuric acid (SO 3 ) to lead sulphate by factor 
 a 7875, and deduct from the total lead weighed as sulphate. 
 Then if neither whiting or magnesium carbonate is present 
 calculate carbonic acid to basic carbonate of lead by factor 8.8
 
 46 
 
 This will usually satisfy all the lead and is checked by cal- 
 culating the basic carbonate of lead to lead sulphate by 
 factor 1.172, and substracting the result from the total lead 
 sulphate. From the remaining lead sulphate deduct that 
 calculated from the sulphuric acid and should any yet re- 
 main it is figured to lead oxide (PbO) by using factor .735. 
 (see note 2). If whiting and magnesium carbonate are 
 present it will be necessary to first deduct the CO 2 , combined 
 with them by multiplying calcium carbonate by factor M 
 and magnesium carbonate by factor .52L 
 
 When Gypsum is Present. If gypsum be present, cal- 
 culate the sulphuric acid (SO 3 ) in it by factor .564 and deduct 
 from the total sulphuric acid, calculating any remaining 
 to lead sulphate by factor 3.78. Now deduct lead sulphate 
 from total lead sulphate and the remaining lead sulphate is 
 calculated to basic carbonate of lead, or, if no carbonates are 
 present, to lead oxide (PbO). If carbonate of lime and 
 magnesium are present deduct the carbonic acid contained 
 in them before combining with the lead. 
 
 The calcium extracted by the nitric acid-alcohol treat- 
 ment and weighed as sulphate, is deducted from the total 
 calcium found and the difference is the lime existing as 
 gypsum. As it is usually fully hydrated it will be necessary 
 to calculate the calcium sulphate (CaSO 4 ) to CaSO 4 2H 2 O by 
 factor 1.26, in which form it exists. Zinc is weighed as oxide 
 and exists as such in the sample.
 
 4. * Analyses of the Solid Portion of "Ready-Mixed" 
 Paints. (Light Tints.) 
 
 SSSg : :S2 
 
 incjr-id ' *-OM 
 
 ill 
 
 * By the Author. 
 
 ill 

 
 - 48 - 
 
 5. * Analyses of "White Paste Paints. 
 
 3 
 
 S33 : :$ : g 
 
 
 * By the Author. 
 
 * ^*CO t I i-( 
 
 S 8 ^ 1 8
 
 APPENDIX. 
 
 1. Estimation of Turpentine, Benzine and Water. 
 
 A majority of the mixed paints contain varying amounts 
 of "turps," (turpentine) or benzine or water, and their esti- 
 mation is attended with more or less difficulty. Owing to the 
 proneness of "turps" to oxidize when exposed to the air any 
 method depending on its distillation and condensation is 
 liable to give results too low, as oxidation products are formed. 
 A method for the estimation of water, "turps" and benzine 
 has been proposed by Vernon J. Hall, Ph.D., and which has 
 given excellent results, consists in mixing the sample with 
 lead carbonate (PbCO 3 ) (previously dried in an air oven at 
 100 C.,) until a dry powder is obtained, and then distilling, 
 using a special condenser. As seen in the cut the condenser 
 has an inner tube through which the neck of the retort passes, 
 thus enabling the latter to be removed at the end of the 
 operation if it becomes necessary to apply a flame to drive 
 down any drop of condensed water or "turps" that frequently 
 adhere to the inner tube of condensers. 
 
 From 20 to 25 grams of the thoroughly mixed sample 
 are quickly weighed out in a small beaker and the beaker 
 then filled with the carbonate of lead. By the aid of a 
 spatula the whole is now mixed and chopped into fine pow- 
 der. If it appears sticky more carbonate of lead is added 
 and a sufficient quantity has been added when the mixture is 
 a dry fine powder. It is now transfered to the retort by the 
 aid of a sheet of glazed paper, folded funnel shaped) and any 
 dust brushed down with a brush. 
 
 The graduate H is also weighed. Connect the apparatus 
 and apply at first a low flame and gradually increase the heat 
 until a temperature of about 120 0. is obtained which will be 
 sufficient to volatilize all the water and benzine. Keep at 
 the temperature until nothirg more comes over. Now draw
 
 60 
 
 the retort from the condenser and with the aid of the flame 
 drive the remaining drops down into the graduate. The lat- 
 ter with its contents are weighed, and the increase of weight 
 
 A A Retort. 
 
 B Condenser. 
 
 CC Inner Tube through which 
 
 neck of condenser passes. 
 D Thermometer. 
 
 Inlet Water. 
 Outlet Water. 
 Bunsen Burner. 
 Graduate (1C c.c. 
 capacity;. 
 
 equals water and benzine. If water is present it will be the 
 lower layer and the volume of each is noted. Now increase 
 the temperature to 170 C., at which point all "turps" will
 
 - 51 
 
 come over. When distillation ceases again remove the retort 
 and with the flame drive down into the graduate any adhering 
 drops. Read the volume. Any increase is due to turpentine. 
 Weigh the graduate and contents, the increase in weight is 
 total water, benzine and "turps." The percentages are found 
 
 as follows: Suppose 25 grams of sample were taken and the 
 distillate weighed 2.1 grams, then 
 
 total distillation. 
 
 25 a4 per centi by 
 
 Now the volumes read, benzine 1.2 G.C., water L5 c.0., "turps" 
 a3 c.c., total aoo c.c., then 
 
 8.4xi.2_ a36 per ^^ benzine by weight 
 
 Likewise, we would find 4.2 per cent water and &4 per 
 cent "turps." Deducting this total distillate 11.2% from the
 
 52 
 
 total mixing fluid as found in Chap. L, the difference is the 
 percentage of oil by weight 
 
 A method has been proposed by H. Joshua Phillip, 
 F.LC., F.C.S. (Chemical News, Vol. LXIII, No. 1646,) 
 which consist of distilling in a stream of coal gas thus avoid- 
 ing exposure to air. As shown in the illustration the appara- 
 tus consists of a retort A into which is fitted a three-way 
 tube B by means of a tight fitting cork In the tube B is 
 a thermometer supported by a cork at C and D is a rubber 
 tube connecting with a supply of coal gas. The distillate is 
 collected in the small flask F. In F is fitted a small tube G 
 for the exit of the coal gas. The flask F is allowed to rest in 
 a basin of cold water. The thoroughly stirred sample is 
 poured into a small beaker and quickly weighed. The tube 
 B being removed the sample is poured into the flask until 
 the beaker is quite well drained. Now weigh again, the 
 difference in weight being the amount of sample taken. 
 Connect the apparatus and start slow stream coal gas and 
 allow to run for some time. Then light at G and regulate so 
 that the flame will be about three- eigth of an inch in length. 
 Now apply heat and proceed as detailed for the distillation 
 and estimation of "turps," benzine and water. 
 
 Estimation of Oil in Flaxseed and Oil Cake. 
 
 The best solvent for extracting the oil from the flaxseed 
 and cake is carbon bisulphide providing it can be obtained 
 free from sulphur. The latter may be detected by evaporat- 
 ing a portion to dryness in a water bath. Should sulphur be 
 present which is invariably the case it may be removed by 
 carefully distilling off the carbon bisulphide. The grade 
 that is made by Schuchart (Germany) is very pure and con- 
 tains such a slight trace that it need not be taken into consid- 
 eration. 
 
 To estimate the oil; five grams of the oil cake are used or 
 three grams of ground flaxseed and carefully brushed into a 
 four ounce Erlenmeyer flask. Then add about 25 c.c. carbon 
 bisulphide, cork loosely, and allow to stand about twelve 
 hours with occasionally a gentle agitation. Pour the quite 
 clear carbon bisulphide in a filter allowing it to run into a 
 weighed beaker of about 200 c.c. capacity. Add about 15 c.c.
 
 53 
 
 more bisulphide to the residue agitate gently and allow to 
 stand about 15 minutes or until the sample is pretty well 
 settled, again pour off and repeat the treatment about four 
 times. Then with the aid of a wash bottle containing carbon 
 bisulphide wash the remaining seed or meal to the filter, 
 finish the washing of the beaker allowing the bisulphide to 
 run on the filter and thoroughly wash the oil from the paper. 
 When the carbon bisulphide is all run through place the 
 beaker and contents in a warm place until the carbon bisul- 
 phide is evaporated then heat in an air oven at a temperature 
 of 110 C. for about 15 minutes. Cool and weigh. The 
 increase of weight equals the oil which multiplied by 100 and 
 divided by the weight of sample taken gives the percentaga
 
 54 
 
 2. List of the Principal Pigments with Chemical 
 Formula and Trade Names. 
 
 WHITE PIGMENTS. 
 Chemical Name. Formula. Trade Name. 
 
 Sulphate of Barium . . . BaSOi Barytes, "Blanc Fixe." 
 
 Carbonate of Calcium. CaCO 3 Whiting, Lime Carbonate 
 
 Lime, Paris White, En- 
 glish White, Spanish 
 White, Marble Dust. 
 
 Sulphate of Calcium . . CaSO 4 2H 2 O Gypsum, Terra Alba, 
 
 Plaster of Paris (CaSO 4 
 2H 2 O, when dehydrated.) 
 
 Sulphate of Strotium . . SrSO 4 Strontian White. 
 
 Sulphate of Lead PbSO 4 Sublimed Lead, "White" 
 
 Lead. 
 
 Silica SiO 2 Silex, Silver White, Wood 
 
 Filler, Infusorial Earth, 
 Ground Quartz. 
 
 Oxide of Zinc ZnO Zinc White, Zinc Oxide, 
 
 Zinc. 
 
 Hydrated Silicate of 2 SiO 2 Al 2 032H 2 O China Clay, Clay. 
 
 Alumina. 
 
 Carbonate of Magn'm . MgCO 3 Magnesite. 
 
 Silicate of Magnesium . 46# to 58# SiO 2 Talc, Soapstone, French 
 
 29# " 34# MgO Talc, Steatite. 
 
 02# 07#H,0 
 
 (with small amounts Iron 
 Oxide and Alumina.) 
 
 Sulphide of Zinc ZnS Mixed with Barytes and 
 
 Zinc Oxide is "Lithopbone." 
 Basic Carb'te of Lead.2PbCO 3 PbH 2 O 2 White L'd, Corroded L'd. 
 
 GREENS. 
 
 Pure Chrome Green . . . Cr 2 O 3 Chrome Greens. 
 
 Chrome Green PbCrO 4 Chrome Greens 
 
 PbSO 4 
 
 2PbCO 3 +PbH 2 O 2 
 
 K 2 Fe22Fe(CN)6 
 
 Chrome Green K 2 Fe 2 (FeCN)2 BrunswickGreen. 
 
 PbCrO 4 
 
 PbSO 4 
 
 BaSO 4 
 
 "Scheele's" Green CuAsO 3 CuO2H 2 O 
 
 "Emerald" Green 7Cu2C 2 H 3 Oo3CuAs 2 O 4 .
 
 55 
 
 BLUES. 
 Chemical Name. Formula. Trade Name. 
 
 Ultramarine Composition by Gmelin 
 
 SiO, 47.306 
 
 A1 2 O 3 22-000 
 
 Na 2 O 12.063 
 
 S 0.188 
 
 CaCOs 
 
 CaO 1.5:16 
 
 H 2 SO 4 4.679 
 
 Water, etc... 12.218 
 
 Prussian Blue Potassium Ferric Ferro- Berlin Blue, Chinese 
 
 cyanide K 2 Fe22Fe(CN) 6 Blue. 
 REDS. 
 
 Lead Monoxide PbO Litharge, Lead Oxide, 
 
 Massicot. 
 
 Lead Oxide PbsO 4 Red Lead, Orange Red. 
 
 Basic Chromate of L'd . PbCrO 4 -f-PbO Dark or Basic Chromate 
 
 of Lead, Chrome Red, 
 Scarlet Lead, Derby Red. 
 
 Sulphide of Mercury . . HgS Mercury Vermilion, Chi- 
 nese Vermilion. 
 
 Red Lead or Orange Mineral Artificial Vermilion, Am- 
 
 Barytes as a base tinted erican Vermilion, Ver- 
 
 with eosine (aniline). milionettes, Aniline 
 
 Reds, Royal Reds. 
 
 Oxide of Iron FejOs Indian Reds, Rouge,Vene- 
 
 tian Red, Princes Mineral, 
 Tuscan Red. 
 
 Carbonate of Iron FeCOs Crocus. 
 
 YELLOW AND ORANGE. 
 
 Chromate of Lead PbCrO 4 +PbSO 4 Chrome Yellow, Chrome, 
 
 (Sometimes white lead) Lemon Chrome. 
 
 Chromate of Lead PbCrO 4 Orange Chrome. 
 
 Ochres and Siennas: Silicate of alumina colored by hydrated ferric oxide 
 in ochres and hydrated ferric oxide with manganese oxide in Siennas. 
 BLACK PIGMENTS. 
 
 Carbon C Lamp Black, Gas Black. 
 
 Carbon, with Phos- 60# Phosphate of .... Ivory Black, Bone Black, 
 phate of Calcium. Calcium. 15$ Car- Drop Black, Animal 
 bonate of Calcium Black, 
 and some silica, iron 
 and alumina. 25$ 
 Carbon 
 
 Graphite C Graphite. 
 
 BROWN PIGMENTS. 
 
 Umber, both raw and "burnt," is the chief brown pigment. Essentially 
 ochres or siennas but contain more manganese, the latter varying from 
 7 to 12 per cent. MnO 2 .
 
 - 56 - 
 
 3. Atomic Weights. 
 
 Name. 
 Aluminium.. 
 Antimony . . . 
 Arsenic 
 
 Sym- 
 bol. 
 . Al 
 ..Sb 
 ..As 
 
 Quanti- 
 valence. 
 
 IV 
 V 
 
 v 
 
 Atomic 
 Weight. 
 
 27.0 
 120.0 
 74.9 
 
 Name. 
 Mercury 
 Molybdenum . 
 Nickel 
 
 Sym- 
 bol. 
 Hg 
 .Mo 
 
 Ni 
 
 Quanti- 
 valence. 
 II 
 VI 
 VI 
 
 Atomic 
 Weight. 
 
 200.0 
 96.0 
 590 
 
 Barium 
 
 ..B 
 
 II 
 
 136.80 
 
 Nitrogen 
 
 N 
 
 v 
 
 14.0 
 
 Bismuth 
 
 Bi 
 
 v 
 
 2100 
 
 
 Os 
 
 IV 
 
 1990 
 
 Boron. . 
 
 B 
 
 III 
 
 11.0 
 
 Oxvcen 
 
 o 
 
 II 
 
 160 
 
 Bromine. . 
 
 . Br 
 
 I 
 
 80.0 
 
 Palladium 
 
 Pd 
 
 IV 
 
 1060 
 
 Cadmium . . . 
 Caesium 
 
 ..Cd 
 ..Cs 
 
 II 
 I 
 
 112.0 
 133.0 
 
 Phosphorus . . 
 Platinum 
 
 .P 
 Pt 
 
 V 
 IV 
 
 31.0 
 197.0 
 
 Calcium .... 
 
 ..Ca 
 
 II 
 
 40.0 
 
 Potassium. . . . 
 
 K 
 
 I 
 
 39.1 
 
 Carbon 
 Cerium 
 Chlorine 
 
 ..C 
 ..Ce 
 
 ..Cl 
 
 IV 
 
 III 
 
 I 
 
 12.0 
 141.2 
 35.5 
 
 Rhodium 
 Rubidium 
 Ruthenium. 
 
 .Ro 
 .Rb 
 "Rn 
 
 IV 
 
 I 
 
 IV 
 
 104.0 
 85.0 
 104.0 
 
 Chromium. . . 
 Cobalt 
 
 ..Cr 
 ..Co 
 
 VI 
 VI 
 
 52.4 
 59.0 
 
 Selenium 
 Silicon 
 
 .Se 
 
 Ri 
 
 II 
 
 IV 
 
 79.0 
 28.0 
 
 Columbium 
 
 Cb 
 
 v 
 
 94.0 
 
 Silver 
 
 Ae 
 
 I 
 
 1080 
 
 Copper. 
 
 Cu 
 
 II 
 
 63.1 
 
 Sodium 
 
 Ni 
 
 I 
 
 23.0 
 
 Didymium .. 
 Erbium 
 
 ..D 
 
 . .E 
 
 III 
 III 
 
 147.0 
 169.0 
 
 Strontium . . . 
 Sulphur 
 
 .Sr 
 B 
 
 II 
 
 II 
 
 87.5 
 32.0 
 
 Fluorine 
 Gallium 
 
 ..P 
 Ga 
 
 I 
 
 III 
 
 19.0 
 699 
 
 Tantalum 
 Tellurium 
 
 .Ta 
 Te 
 
 V 
 II 
 
 182.0 
 128.0 
 
 Glucinum... 
 Gold 
 
 ..Gl 
 ..Au 
 
 II 
 
 III 
 
 9.2 
 196.2 
 
 Thallium 
 Thorium 
 
 .Tl 
 Th 
 
 I 
 
 IV 
 
 204.0 
 231.5 
 
 Hydrogen . . . 
 
 . .H 
 
 I 
 
 1.0 
 
 Tin 
 
 Sn 
 
 IV 
 
 118.0 
 
 Indium 
 Iodine 
 
 ..In 
 I 
 
 III 
 
 I 
 
 113.4 
 
 12685 
 
 Titanium 
 Tungsten. 
 
 .Ti 
 W 
 
 IV 
 IV-VI 
 
 50.0 
 1840 
 
 Iron 
 
 Fe 
 
 VI 
 
 56.0 
 
 Uranium 
 
 TT 
 
 VI 
 
 2400 
 
 Lanthanum. 
 Lad 
 
 ..La 
 . Pb 
 
 III 
 
 II 
 
 139.0 
 207.0 
 
 Vanadium ... 
 Yttrium .... 
 
 .V 
 Y 
 
 v 
 
 III 
 
 5L2 
 60.0 
 
 Lithium 
 
 ..Li 
 
 I 
 
 7.0 
 
 Zinc 
 
 7,n 
 
 II 
 
 65.0 
 
 Magnesium. . 
 Manganese . . 
 
 ..Mg 
 ..Mn 
 
 II 
 
 VI 
 
 24.0 
 55.0 
 
 Zirconium . . . 
 
 .Zr 
 
 IV 
 
 90.0
 
 4. Measures and Weights. 
 
 MEASURES OF CAPACITY, 
 
 
 Grains of 
 Water 
 
 Cubic 
 Ceuti- 
 
 
 Gals Qts. Pts. Fl. Oz. FL Dr. at62F. 
 
 metres. 
 
 
 1=4 = 8 = 128 = 1,024 = 58,318.00 = 
 
 3,785,200 
 
 
 1 = 2= 32= 256 = 14,579.50 = 
 
 946,300 
 
 
 1 = 16 = 128 = 7,289.75 = 
 
 473,150 
 
 
 1 = 8 = 455.61 = 
 
 29,570 
 
 
 1 = 56.98 = 
 
 3,690 
 
 1 
 
 English imperial gallon = 277.274 cu. in. = 70,000.00 = 
 
 4,543,000 
 
 1 
 
 " wine or Win- 
 
 
 1 
 1 
 
 chester gal. = 231.000 " = 58,318.00 = 
 " corn gallon = 268.000 " = 67,861.00 = 
 ale " = 282.000 " = 71,193.40 = 
 
 3,785,200 
 4,402,900 
 4,619,200 
 
 
 1 cu. ft. = 283.15 cc. 
 
 
 
 1 cu. in. = 16.38 " 
 
 
 
 0.061027 " = 1 " 
 
 
 
 LINEAR MEASURES. 
 
 
 
 1 yd = 3 ft. = 36 in. = 0.91438 metre. 
 
 
 
 1ft. = 12 in. = 0.30480 " 
 
 
 
 lin. = 0.02540 " 
 
 
 
 39.3708 in. = 1.00000 " 
 
 
 
 TBOY WEIGHT. 
 
 
 lib. = 12 oz. = 240 cwt. 5,760 grs. = 373.2419 
 
 grammes. 
 
 
 1 = 20 480 " = 31.1035 
 
 
 
 
 1 = 24 " = 1.5552 
 
 < 
 
 
 1 " = 0.0648 
 
 
 
 AvoiRDUPoib WEIGHT. 
 
 1 greas ton = 20 cwt. == 2,240 Ibs. = 1,016.00 kilogrammes. 
 1 = 112 " = 50.80 
 
 Oz. 
 
 lib. = 16 
 1 
 
 1 net ton = 2,000 Ibs. = 
 1 cu. ft. of water at 62 F. = 
 1 cu. in. " " " " = 
 
 Grs. Troy. Grammes. 
 = 7,000.00 = 453.5926 
 = 437.50 = 28.3495 
 
 907 kilogrammes. 
 
 62.3550 Ibs. Av. = 28315.0000 grammes. 
 0.0361 " " = 16^862 
 
 APOTHECARIES WEIGHT. 
 
 1 Ib. = 12 oz. = 96 dr. = 288 scruples = 5,760 grains = 373.2419 grams. 
 
 1 " = 8 " = 24 480 31.1035 " 
 
 1 = 3 60 3.8879 " 
 
 1 20 1.2960 " 
 
 0.0022 Ib. Av. 0.03527 oz. Av. = 15.4328 = 1.0000 "
 
 ..INDEX., 
 
 Aluminum, in China Clay 11 
 
 American Vermilion 55 
 
 Ammonium Acetate Solution. .33 
 
 Aniline Red 55 
 
 Animal Black 55 
 
 Analyses, table of white and 
 
 tinted "Mixed Paints" 47 
 
 Analyses, table of white "Paste 
 
 Paints" 48 
 
 Analysis of Barytes, 16; Cal- 
 cium Carbonate, 7; China 
 Clay, 15; Gypsum, 15; Magne- 
 site, 17; Magnesium Silicate, 
 18; Silica, 15; White Lead, 24; 
 
 Zinc Oxide 19 
 
 Apparatus for estimation of 
 
 carbonic acid in white lead. . . 27 
 Apparatus for estimation of 
 Turpentine, Benzine and 
 
 Water 50 
 
 Apparatus for white lead an- 
 alysis 29 
 
 Appendix 49 
 
 Arbitrary Formulae 43 
 
 Artificial Vermilion 55 
 
 Atomic Weights, table of 56 
 
 Basic Carbonate of Lead 24-54 
 
 Basic Chromate of Lead 55 
 
 Barium Carbonate and Barium 
 
 Sulphate, analysis of 45 
 
 Barium Carbonate, estimation 
 
 of in pain.ts 42 
 
 Barium Sulphate, analysis of.. 16 
 
 Barytes 16-54 
 
 Barytes, estimation of in 
 
 paints 40 
 
 Barytes, qualitative tests for. .17 
 Benzine, estimation of in 
 
 paints 49 
 
 Black Pigments 55 
 
 Blanc Fixe .. ...16-54 
 
 PACK 
 
 Blank Tests 2 
 
 Blues 55 
 
 Bone Black 55 
 
 Brown Pigments 55 
 
 Brunswick Green 54 
 
 Calcium Carbonate, 7; in whit- 
 ing, 8; estimation of, in 
 
 paints 42 
 
 Calcium in china clay 14 
 
 Calcium Sulphate in whiting. . 9 
 Carbon Bisulphide, for extrac- 
 tion of oil in flaxseed 52 
 
 Carbonic Acid, estimation of in 
 
 white leads 25 
 
 Centrifugal Machine, for sepa- 
 ration of oil and pigments. . . 5 
 
 China Clay 54 
 
 China Clay, analysis of, 15; an- 
 alysis of, 11; composition of, 
 10; estimation of, in paints. .40 
 
 Chinese Vermilion 55 
 
 Chrome 55 
 
 Chrome Greens 54 
 
 Chrome Red, 55 
 
 Chrome Yellow 55 
 
 Clay 54 
 
 Coloring Pigment 43 
 
 Combustion Method for white 
 
 lead 28 
 
 Corroded Lead 54 
 
 Crocus 55 
 
 Derby Red 55 
 
 Drop Black 55 
 
 English White 54 
 
 Ferrous Sulphate, for standar- 
 dizing potassium perman- 
 
 gate solution 13 
 
 Filtering Apparatus 37 
 
 French Talc 54 
 
 Fresenius, study of 1 
 
 Gas Black... ...55
 
 PAGE 
 
 General Precautions 1 
 
 Gooch Crucible and Cone 2 
 
 Gooch Crucible, to prepare for 
 
 use 36 
 
 Graphite 55 
 
 Green Pigments, list of 54 
 
 Gypsum, 54; analysis of, 10; Cal- 
 culations when present in 
 complicated mixture, 46; 
 
 qualitative test for 33 
 
 Hall, Vernon, J., method of. . .49 
 
 Indian Reds 55 
 
 Infusorial earth 54 
 
 Insoluble matter in zinc pig- 
 ments 23 
 
 Insoluble residue in paints. . . .40 
 
 Iron in China clay 11 
 
 Iron and Alumina in whiting. . 8 
 Iron, separation from alumina. 12 
 
 Ivory Black 55 
 
 Kaolin 10 
 
 Lamp Black 55 
 
 "Leaded Zinc," mention of. . .31 
 Lead in white lead, estima- 
 tion of 24 
 
 Lead in zinc oxide, estima- 
 tion of 19 
 
 Lead Oxide in paints 46 
 
 Lead Sulphate, estimation of 
 
 in mixtures 39 
 
 Lead Sulphite 34 
 
 Lemon Chrome 55 
 
 Lame Carbonate 54 
 
 Linseed Oil, estimation of in 
 
 flax seed and oil cake 52 
 
 Litharge 55 
 
 Lithophone 54 
 
 Magnesite 17-54 
 
 Magnesium Carbonate, analy- 
 sis of, 17; estimation of, in 
 paints, 42; in whiting, 9; in 
 
 china clay 14 
 
 Magnesium Silicate, composi- 
 tion of, 18; estimation of, in 
 paints 41 
 
 PAGE 
 
 Marble Bust 54 
 
 Massicot 55 
 
 Measures and Weights 56-57 
 
 Mercury Vermilion 55 
 
 Mixing Fluid 3 
 
 Oil, percentage of, in paints, 4; 
 separation, by centrifugal 
 machine, 5; oil, separation 
 from sample, 3; separation, 
 
 with nitric acid 6 
 
 Ochres 55, 
 
 Orange Chrome 55 
 
 Orange Lead 55 
 
 Paper, filter 2 
 
 Paris White 54 
 
 Pigments, list with chemical 
 
 formula and trade names 54 
 
 Phillips, H. J., method for dis- 
 tillation of turpentine, ben- 
 zine and water 52 
 
 Plaster of Paris 10-54 
 
 Potassium permanganate solu- 
 tion 13 
 
 Potassium, separation from 
 
 sodium, in china clay 14 
 
 Princes Mineral 55 
 
 Prussian Blue 55 
 
 Quantitative analysis, scheme 
 
 to use 35 
 
 Quanti valence, table of 56 
 
 Qualitative tests, of white and 
 
 tinted paints 32 
 
 Quartz, ground 54 
 
 Reagents, purity of 1 
 
 Red Lead 55 
 
 Rouge 55 
 
 Royal Red 55 
 
 Samples, preparation for an- 
 alysis 3 
 
 Scarlet Red 55 
 
 Scheme to use, in quantitative 
 
 analysis 35 
 
 Siennas .55
 
 PAGE 
 
 Silex 15-54 
 
 Silica, 15; estimation of, in 
 paints, 40; in china clay, 11; 
 
 in whiting 7 
 
 Silver White 54 
 
 Soap stone 18-54 
 
 Sodium, separation from po- 
 tassium in china clay 14 
 
 Solvents, for extraction of oil.. 3 
 
 Soxhlet extractor, for oils 4 
 
 Spanish White 54 
 
 Steatite 18-54 
 
 Strontian White 54 
 
 Sublimed Lead 54 
 
 Sublimed Lead> Calculations 
 
 when present 42 
 
 Sulphate of Calcium. 10 
 
 Sulphate of Zinc, estimation 
 
 of 22 
 
 Sulphuric acid, estimation of in 
 
 zinc oxide or paints 21 
 
 Table of Analyses of ready 
 
 mixed paints 47 
 
 Table of Analyses of white 
 
 paste paints 48 
 
 Talc 18-54 
 
 Terra Alba 10-54 
 
 Testing for Barytes 17 
 
 Thomson, method for the esti- 
 mation of calcium carbonate, 
 gypsum, lead sulphate, etc. . .44 
 
 PAGB 
 
 Turpentine, estimation of, in 
 
 paints 49 
 
 Tuscan Red 55 
 
 Ultramarine 55 
 
 Umber 55 
 
 Venetian Red 55 
 
 Vermilionettes , 55 
 
 Vermilions 55 
 
 Water, distilled _ 2 
 
 Water, estimation of, in paints, 
 49; in china clay, 15; in gyp- 
 sum 10 
 
 Weights, table of 56 
 
 White Lead, 54; analysis of, 24; 
 
 composition of ..,...<... . , . 24 
 White Lead, estimation of in 
 
 paints 41 
 
 White Pigments 7 
 
 Whiting, 54; analysis of 7 
 
 Wood Fillers 54 
 
 Zinc, 54; metallic, for standar- 
 dizing potassium permanga- 
 nate solution 13 
 
 Zinc Oxide, analysis of, 19; esti- 
 mation of, in paints 41 
 
 " Zinc-Lead," mention of 31 
 
 Zinc Pigments, analysis of. . . .23 
 Zinc Sulphide, for white pig- 
 ments 54 
 
 Zinc Sulphite, mention of 34 
 
 Zinc White ,...54
 
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 'BRANCHES; Chicago, Paris, Bombay, Vienna, Sydney, Etc. 
 
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 WORKS: Elizabethport, N. J., U. S. A.
 
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 Special Catalogues 
 
 ^Apparatus for . and 
 
 Taint and Color l^lj|gs!s^f ' Trices upon 
 
 Determinations ^B 111 (Application 
 
 IMPORTERS AND 'DEALERS IN 
 
 Chemicals .... 
 and Chemical Apparatus 
 
 ...FOR... 
 
 Analytical Laboratories 
 
 Microscopes, and other Instruments for 
 Scientific Investigations. 
 
 106-108 Wabash Avenue, - - CHICAGO.
 
 Established 1832. Incorporated 1882. 
 
 Valentine & Company 
 
 HENRY C. VALENTINE, PRESIDE 
 
 ^Manufacturers of 
 High Grade... 
 
 Coach and Railway Varnishes 
 and Colors 
 
 NEW YORK, 
 
 57 Broadway. 
 
 BRANCH HOUSES: 
 
 CHICAGO, BOSTON, 
 
 390 Wabash Avenue. J64 Purchase Street. 
 
 PARIS, 
 2* Rue de Lappe. 
 
 Our VARNISHES, GROUND ROUGHSTUFF and COACH- 
 PAINTERS' COLORS are kept in stock, and are 
 for sale in the United States by the 
 Leading Dealers in Paints and 
 Carriage-Makers' Supplies.
 
 <Parf 
 
 c/lbsolutely 
 
 Sold 
 Subject 
 to Chemical 
 Analysis^ 
 
 of wonderful covering capacity. Of 
 greatest durability. That looks the 
 best. That costs less in the end ... 
 
 We Guarantee the cMonarch cMixed 
 
 Is it not safer to pay the price of a good article and be satisfied, than to run 
 the chances with cheap goods? Painting- is too expensive, and the work too 
 important to risk results. The experience of those who practice economy is, that 
 it pays to use the best. 
 
 Monarch Paint has been before the public for fifteen years, and enjoys an 
 enormous trade from New England to the Pacific Coast. Wherever tried, Monarch 
 has proved to be what is claimed for it a heavy bodied Lead, Zinc and Oil Paint; 
 absolutely pure materials only, and those of the best quality being used in its manu- 
 facture. Color card on application. 
 
 SENOUR MANUFACTURING CO. 
 
 Pioneers of Tare Taints.
 
 PRICE LIST 
 
 ..OF... 
 
 V 
 
 r alentines Coach Varnishes 
 
 FINISHING SSSr&il 
 
 earing- Body Varnish $6.00 
 
 edium Drying Body Varnish 6.00 
 
 Elastic Gear Varnish 5.00 
 
 One Coat Coach Varnish 4.50 
 
 One Coat Gear Varnish... ..3.50 
 
 RUBBING 
 
 Hard Drying- Body Varnish (4-day rubbing-) 5.00 
 
 Quick Leveling- Varnish (2-day rubbing-) 4.00 
 
 Flatting Varnish 3.00 
 
 Black Japan 4.50 
 
 Black Color-and- Varnish... ..4.00 
 
 MISCELLANEOUS 
 
 No. 1 Black Varnish 1.50 
 
 Carriage Top Dressing 4.00 
 
 Quick Black Lacquer 4.00 
 
 Japan Gold Size 3.50 
 
 Crown Coach Japan 1.75 
 
 Dark Permanent Wood Filling 4.00 
 
 Light Permanent Wood Filling 4.00
 
 ORGANIZED INCORPORATED 
 
 1868. 1883. 
 
 IN BUSINESS 31 YEARS. 
 
 We sold the first bill of READY MIXED 
 PAINT in Chicago May 12, 1868, and are still 
 in the business. 
 
 We are now building a new thoroughly 
 equipped factory, corner of Fulton and Car- 
 penter Streets, where our facilities for manu- 
 facture will be unsurpassed. 
 
 Our Paints speak for themselves. We 
 prefer the opinions of customers to statements 
 of our own. 
 
 Geo. W. Pitkin Co. 
 
 CHICAGO. 
 MAKERS OF PAINTS AND COLORS
 
 The La<wson Varnish Co/s 
 
 DESCRIPTIVE PRICE LIST 
 
 OF 
 
 High Grade Varnishes 
 For House ^Painters and Decorators 
 
 INSIDE LUSTRO, 
 
 For the finish and preservation of all hard wood-work 
 in house and public buildings. 
 
 OUTSIDE LUSTRO, 3.50 
 
 For use on front doors, vestibules, window-casings, 
 store-fronts, signs, etc. 
 
 ELASTIC FLOOR, ------- 2.50 
 
 For finishing and preserving hard wood floors. Its use 
 enables them to be kept clean with the least labor. 
 
 PALE RUBBING, 3.00 
 
 A nearly colorless varnish for interior decoration es- 
 pecially adapted for use on White Enamel work. 
 
 EXTRA HARD OIL FINISH, 2.00 
 
 For interior finishing of natural woods. Good body, 
 dries quickly and hard, with good luster. 
 
 302 Wabash Avenue, J68 Purchase Street, 
 
 CHICAGO. BOSTON. 
 
 57 Broadway, New York. 
 FACTORY: Chicago.
 
 UNIVERSITY OF CALIFORNIA AT L.OS ANGI 
 THE UNIVERSITY LIBRARY 
 
 This book is DUE on the last date stamped below 
 
 MAY 2 5 1848 
 JUL9 1947 
 
 *L> 
 MAR 6 1953 
 
 UN 1; 
 
 AUG 
 JAN 2 2 196Z 
 
 REC'D 
 
 IIEC'D ID-UN. 
 
 n 
 
 
 UNIVERSITY of CALIFORNIA 
 
 AT 
 
 LOS ANGKLES 
 LIBRARY
 
 ,^,?,^RN REGIONAL LIBRARY>ACILITY 
 
 AA 001 034 903 3