UC-NRLF 
 
LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 Class 
 
MACHINERY AND APPARATUS 
 
 FOR 
 
 MANUFACTURING CHEMISTS 
 
MACHINERY AND APPARATUS 
 
 FOR 
 
 MANUFACTURING CHEMISTS 
 
 BY 
 
 JAMES C. SHEARS 
 
 Atsffc. M. Inst. C.E. 
 
 (ALL RIGHTS RESERVED.) 
 
 LONDON 
 E. MARLBOROUGH & CO., 51, OLD BAILEY, E.G. 
 
HAVING for many years been engaged in the manu- 
 facture of Pharmaceutical Laboratory Plant, and in 
 the erection of some of the most modern factories for 
 the production of crude and fine chemicals, food 
 stuffs, soap, candles, etc., etc., and $lso of distilleries 
 dealing with alcohol in every form, I venture to bring 
 these notes before the various trades, in the hope 
 that they may be of some assistance to those who 
 may desire to establish factories requiring such plant 
 as is herein described. 
 
 JAMES C. SHEAES. 
 
 LONDON, December, 1895. 
 
 12999V 
 
CONTENTS 
 
 PAGE 
 
 CHEMICAL FACTORIES 
 
 STEAM BOILERS 
 
 EVAPORATING PANS 14 
 
 COPPER STEAM PANS 16 
 
 ENAMELLED IRON PANS 17 
 
 PEWTER STEAM PANS 19 
 
 TILTING PANS . 
 
 STEAM BOILING COILS 20 
 
 VACUUM PANS 24 
 
 STIRRERS 29 
 
 BOILING FOUNTAINS 
 
 DISTILLATION 31 
 
 ESSENTIAL OIL DISTILLATION . . . . . 34 
 
 ALCOHOL STILLS 36 
 
 ALMOND* OIL STILLS .... 36 
 
 PORTABLE STILLS 37 
 
 MINT STILLS 38 
 
 ACETIC ACID STILLS 39 
 
 AUTO STILL 41 
 
 EARTHENWARE STILLS 
 
 CARAWAY OIL STILLS . - 44 
 
 BALNEUM STILLS . . . . . .45 
 
 VACUUM STILLS 47 
 
 WATER DISTILLING APPARATUS 48 
 
 CONDENSERS 50 
 
 vii 
 
viii CONTENTS 
 
 PAGB 
 
 SANDAL OIL DISTILLATION 53 
 
 SEPARATORS 55 
 
 RECEIVERS 56 
 
 DRUG MILLS 56 
 
 DISINTEGRATORS 58 
 
 MACERATORS . 59 
 
 DIGESTERS 60 
 
 COOKING BOILERS 61 
 
 DYE EXTRACTION . ' . 62 
 
 SUPERHEATED STEAM . . . . . . .63 
 
 MALT EXTRACT PLANT 65 
 
 STEEL'S MASHING MACHINE 68 
 
 CITRATE PANS 69 
 
 EMULSIFIERS 70 
 
 PERCOLATORS 72 
 
 PERFUME EXTRACTORS 72 
 
 LIME AND LEMON JUICE CONCENTRATORS ... 75 
 
 LIME OIL EXTRACTORS ....... 77 
 
 HYDRAULIC PRESSES 78 
 
 ALMOND OIL PRESSES 80 
 
 PUMPS 81 
 
 PIPES . . . 82 
 
 CUBIC CAPACITY 82 
 
 MEASURES 83 
 
 THERMOMETERS 84 
 
 PILL MACHINERY 86 
 
 MILK CONDENSING 87 
 
 SOAP MILLING PLANT . . 90 
 
MACHINERY AND APPARATUS 
 
 FOE MANUFACTUEING CHEMISTS 
 
 CHEMICAL FACTORIES. 
 
 An ideal chemical factory should be situated on 
 the bank of a river or canal on the outskirts of a 
 town, with- separated buildings, not exceeding two 
 storeys in height where possible, for each class of 
 manufacture. They should be built in quadrangular 
 form, with ample yard room, and should be connec- 
 ted, by a line of rails running into the yard, with 
 an adjoining railway siding. 
 
 The floors and buildings should be built of fire- 
 proof material, and be capable of being washed all 
 over, and should be commanded by a constant and 
 powerful water supply for this purpose, to avoid 
 risk of fire, as well as to supply the quantity re- 
 quired for manufacturing purposes. 
 
 The whole of the power should be supplied from 
 one main engine, distributed over the various depart- 
 ments by shafting driven by gearing, belts, ropes, 
 or chains. An exact duplicate engine should be kept 
 in readiness for any breakdown, the engines being 
 worked every alternate week, to keep them in 
 thorough working order and condition. 
 
 Steam should be generated in Cornish or Lanca- 
 shire boilers, with large steam-chests to allow of great 
 
10 MACHINERY AND APPARATUS 
 
 ^ \ _ -IIS"'' 1 ' 
 
FOB MANUFACTURING CHEMISTS 11 
 
 steam capacity, the flues from them being carried 
 underground into one large shaft built directly from 
 the ground the boilers, like the engines, to be in 
 duplicate, and worked every alternate week. Steam 
 or hydraulic cranes should be fitted where necessary 
 to each department. 
 
 A large weighbridge and office should be placed 
 near the main entrance, and weighing machines in 
 each department. All heavy machinery should be 
 placed on the ground floors, which should be built 
 of solid concrete covered with hard cement, sloping 
 gradually to the drains. The doors should be amply 
 large enough in each department to admit of any of 
 the machines being got in or out whole, in case of 
 necessity, and the cranes should be amply strong 
 enough to lift the heaviest possible machinery or 
 packages used. 
 
 STEAM BOILERS. 
 
 An unit of heat is the standard measure for the 
 amount of heat absorbed or evolved during any 
 operation, and is the amount of heat required to raise 
 the temperature of a pound of water 1' F. to 32 F. 
 
 A cubic foot of water at 60 F. evaporated to 
 steam at any pressure is equal to one nominal horse- 
 power, 70,000 units of heat, and about two-thirds of 
 this quantity may be reckoned as equal to one net 
 indicated horse-power. 
 
 The unit of power used as a standard is the power 
 necessary to raise 1 Ib. avoirdupois 1 ft. high per 
 minute. 
 
 A horse-power being the power necessary to raise 
 33,000 Ib. 1 ft. high per minute, or 33,000 foot pounds 
 
12 MACHINERY AND APPARATUS 
 
 per minute ; but in calculating the power required 
 for any work allowance must be made for friction. 
 
 The boilers most used for chemical works are of 
 the vertical, Cornish, or Lancashire type. 
 
 Vertical boilers, both with vertical or cross- tubes, 
 cannot be recommended, because they rarely have 
 much steam capacity. They certainly have the 
 advantage of occupying small space, but they require 
 constant attention as to stoking, as they make and 
 lose their steam very quickly. 
 
 Cornish (one-flued horizontal boilers) or Lancashire 
 (two-flued horizontal boilers), with large steam-chests 
 to form steam reservoirs, are most suitable for chemi- 
 cal work, having all the fittings fixed on the steam- 
 chest, insuring dry steam and obviating priming. 
 
 Steam boilers up to 10 h.p. should have 18 ft. per 
 h.p. effective heating surface ; 10 h.p., 14 sq. ft. ; 
 20 h.p., 12 sq. ft. ; and 50 h.p., about 11 sq. ft., with 
 1 sq. ft. of grate surface for small boilers, and f ft. 
 for large above 20 h.p. 
 
 The average quantity of coal consumed per square 
 foot of grate area in ordinary boilers is from 12-14 
 Ib. per hour. 
 
 COMPARATIVE VALUE OF FUELS. 
 
 Welsh Coal 1 
 
 Newcastle Coal 0*885 
 
 Derby and Yorkshire Coal . . . O837 
 
 Lancashire Coal '877 
 
 Scotch -851 
 
 Irish Anthracite T088 
 
 French average O8S4 
 
 Lignites average '736 
 
 Welldrew Peat '500 
 
 Coke average . . . . *995 
 
 Oak -500 
 
 Pine -276 
 
FOR MANUFACTURING CHEMISTS 
 
 13 
 
 All steam boilers should be tested by hydraulic 
 pressure to double their working pressure, and be 
 thoroughly inspected at stated intervals, and should 
 be blown out at each week end, if possible. 
 
 All fittings should be connected to the boilers by 
 flanges, and all the cocks should be safe bottom and 
 gland cocks. 
 
 There should be two sets of water-gauges on each 
 boiler, and two safety valves, one either dead weight 
 or spring type, and the other of the lever type. 
 
 An anti-priming pipe should be attached to the 
 steam stop-valve r and an internal distributing pipe 
 to the feed- valve. 
 
 Each boiler should have two separate means of 
 water supply in case of accident: one to be some 
 form of feed pump, and the other some method of 
 steam feed injection-. 
 
 Cornish, or single-flued boilers, and also Lancashire 
 two-flued boiler&j are usually made from 3 ft. to 6 ft. 
 diameter, and Lancashire, or double- flued boilers, 
 from 5 ft. 6 in. to 8 ft. diameter. The following 
 tables give approximate dimensions for both types : 
 
 CORNISH BOILERS, ONE FLUE. 
 
 
 
 
 
 Plates for 60 Ib. work- 
 
 Suitable 
 for h.p. 
 
 Diameter. 
 
 Length.- 
 
 Flue 
 diameter. 
 
 ing pressure. 
 
 
 
 
 
 Ends. 
 
 Shell. 
 
 Flues. 
 
 
 ft. in. 
 
 ft. 
 
 ft. in. 
 
 in. 
 
 in. 
 
 in. 
 
 15 
 
 3 9 
 
 24 
 
 2 3- 
 
 y 
 
 h 
 
 TV 
 
 18 
 
 4 
 
 26 
 
 2 6 
 
 T 9 
 
 I 7 * 
 
 TV 
 
 27 
 
 4 6 
 
 28 
 
 2 7J 
 
 * 
 
 iV 
 
 4 
 
 33 
 
 4 9 
 
 28 
 
 2 9 
 
 
 | 
 
 i 
 
 42 
 50 
 
 5 
 5 6 
 
 30 
 30 
 
 3 
 3 3 
 
 I 
 
 A 
 
 i 
 
 I 
 
14 MACHINERY AND APPARATUS 
 
 LANCASHIRE BOILERS, Two FLUES. 
 
 
 
 
 
 Plates for 60 Ib. work- 
 
 Suitable 
 for h p 
 
 Diameter. 
 
 Length. 
 
 Flue 
 diameter. 
 
 ing pressure. 
 
 
 
 
 
 Ends. 
 
 Shell. 
 
 Flues. 
 
 
 ft. in. 
 
 ft. 
 
 ft. in. 
 
 in. 
 
 in. 
 
 in. 
 
 65 
 
 6 
 
 24 
 
 2 3 
 
 T 9 
 
 i 7 
 
 T 7 
 
 76 
 
 6 6 
 
 26 
 
 2 6 
 
 T 9 
 
 iV 
 
 T 7 
 
 85 
 
 6 9 
 
 28 
 
 2 7J 
 
 * 
 
 7 
 
 T 
 
 
 90 
 
 7 
 
 28 
 
 2 9 
 
 
 
 i 
 ~z 
 
 i 
 
 104 
 
 7 6 
 
 30 
 
 3 
 
 * 
 
 \ 
 
 i 
 
 112 
 
 8 
 
 30 
 
 3 3 
 
 H 
 
 T 9 e 
 
 
 Diameter of flue = diameter of shell x 4. 
 
 The i.h.p. is rated on the assumption of 7 sq. ft. 
 of heating surface for each i.h.p. ; in practice, the 
 larger boilers will supply steam for 2 or 3 times the 
 i.h.p. given in the tables. 
 
 For example, a Lancashire boiler 28 ft. x 7 ft. will 
 supply steam for an engine from 150 to 200 i.h.p., 
 and a boiler 30 ft. x 8 ft. is capable of supplying 
 steam for an engine of 350 to 400 i.h.p. 
 
 Boilers should incline about 1 in. in 20 ft. to 
 empty easily. Firebars should incline about \ in. 
 to | in. per foot of length. 
 
 EVAPORATING PANS. 
 
 Copper steam-jacketted evaporating pans should 
 be shallow, in the proportion of about 3| to 1 as 
 their diameter is to their depth. They are best 
 fitted in cast-iron steam jackets on pedestals, and 
 jointed at the rim with flush wrought-iron jointing 
 
FOR MANUFACTURING CHEMISTS 15 
 
16 MACHINERY AND APPARATUS 
 
 ring, or into the copper brim only. The copper 
 should not be less than T 3 in. thick for 20-gallon 
 capacity, and thicker for larger sizes in proportion. 
 
 The following will be found useful sizes and pro- 
 portions : 
 
 20 gallons capacity, 34 in. diameter at throat x 10 in. deep. 
 25 36 , xll 
 
 30 40 
 
 35 42 
 
 40 44 
 
 ^^ ?> jj ^^ )> 
 
 50 46 
 
 x!2 
 x!8 
 x!4 
 x!5 
 
 The copper pans can be silver plated, tinned, or 
 slabbed with solid block tin, as desired. 
 
 To assist rapid evaporation in these pans, what is 
 known as the towel evaporator can be applied to 
 them : it is merely an endless towel carried on top 
 and bottom rollers, the top roller having its carriages 
 fastened to a ceiling overhead, and being driven 
 slowly by a belt from an adjacent shaft, and the 
 bottom being made to dip into the pan revolving 
 in hanging bearings attached temporarily to its 
 brim. The towel in its travel carries with it con- 
 tinuously a quantity of the liquid in a film, which 
 gives forth its vapour rapidly in the atmosphere. 
 
 When the goods are sufficiently concentrated, the 
 towel can be washed out, the washings being added 
 to the bulk, to make up the desired quantity. 
 
 COPPER STEAM PANS. 
 
 Copper steam-jacketed boiling pans, as distinct 
 from evaporating pans, should be semicircular in 
 shape, with light courses added if necessary. They 
 
FOR MANUFACTURING CHEMISTS 17 
 
 should be jointed in cast-iron steam jackets, with 
 wrought-iron jointing bands and cupheaded counter- 
 sunk bolts and nuts, and be mounted, the small sizes 
 on pedestals and the larger on cast-iron columns. 
 Small pans of copper should not be less than -^r in. 
 thick and larger sizes thicker in proportion. 
 
 The following will be found useful sizes and pro- 
 portions : 
 
 20 gallons capacity, 29 in. diameter at throat, 14 in. deep. 
 30 32 16 
 
 40 ?) ? "b ,, ,, ,, ,, lo ,, ,, 
 
 50 38 19 
 
 60 40 ,, 20 
 
 on AA 99 
 
 fy(J )J M ** J >5 >J *^ 
 
 100 ,, ,, 4o ,, .. ^ , 
 
 Every 10 feet of heating surface in a pan may be- 
 reckoned to require one horse-power of steam per 
 hour = 1 cubic foot of water evaporated to steam per 
 hour. 
 
 ENAMELLED IRON PANS. 
 
 Enamelled iron pans are largely used in chemical 
 works for containing and evaporating goods which 
 are required to be free from metallic influence. 
 
 Wrought-iron enamelled pans are far superior to 
 cast-iron, as the enamel adheres to them better ; but 
 on account of the difficulty and expense of making 
 them in any size in one piece, cast-iron is more 
 generally used ; but however good the enamel may 
 be, it soon cracks and comes away from the metal, 
 even when it is carried over a projecting rim stand- 
 ing above the throat of the pan, which, however, is a 
 
18 
 
 MACHINERY AND APPARATUS 
 
 safeguard to some extent. There has always been a 
 difficulty in making pans and vessels with holes cast 
 in them, or which require to be jointed together, or 
 have other parts jointed to them, on account of the 
 enamel breaking away from the edges of the holes 
 in the process of jointing. A cast-iron enamelled 
 vacuum pan is a great desideratum ; but as yet a 
 satisfactory one has not been produced. 
 
 Receivers are made with flat or curved rims, and 
 measure about the same in depth as in diameter. 
 
 5-gallon receivers measure 14 in. diameter inside dimensions. 
 
 10 
 20 
 30 
 40 
 50 
 60 
 70 
 80 
 90 
 100 
 
 18,, 
 24 
 26 ,. 
 29 
 32,, 
 36,, 
 38,, 
 40,. 
 
 42 ., 
 
 43 
 
 Cast-iron enamelled steam-jacketed pans are 
 made in both shallow and deep forms, but usually 
 of the following proportions : 
 
 5 gallons capacity, 16 in. diam. x 8 in. deep inside dimens. 
 
 10 
 20 
 30 
 50 
 60 
 100 
 
 ' 
 
 &<J 
 
 5? 5 
 
 J-U ., 
 
 
 5 
 
 26 
 
 ,. , 
 
 x 15 ,, 
 
 
 , 
 
 29 
 
 11 i 
 
 x 16i 
 
 
 j 
 
 36 
 
 V 5 
 
 x21 
 
 
 1 
 
 40 
 
 11 1 
 
 x23 ., 
 
 
 JJ 
 
 46 
 
 /' ) 
 
 x26 
 
 j 
 
FOR MANUFACTURING CHEMISTS 19 
 
 PEWTER STEAM PANS. 
 
 Pewter steam evaporating pans are costly articles 
 to purchase, but repay their cost in a short time, and 
 are much more satisfactory for evaporating green 
 extracts, etc., than copper pans lined or slabbed with 
 pure tin or enamelled iron pans, neither of which 
 last very long. 
 
 Pewter, such as these pans are made of, should be 
 practically pure English block tin, only tempered 
 sufficiently to enable the metal to be worked, and 
 free from lead and antimony. Steam at 10 Ibs. 
 pressure per square inch is quite the limit of heat 
 that should be applied to them, and no steam jet 
 should be allowed to play directly on to the pewter. 
 
 Steam should be let into the jacket at two or more 
 places under guard plates, so as to evenly divide the 
 expansion over the whole area of the pan, and 
 special care should be taken to free the jacket from 
 air, which expands enormously as it becomes heated, 
 and tends to lift the throat of the pan. The pans 
 are made in sections shaped and burnt together with 
 hot irons, with their own metal freed from flaws, and 
 then hammered and flanged by hand, and planished 
 hard on bright anvil tools. No pan should be 
 made less than f in. thick. They usually vary in 
 size from 2 ft. to 4 ft. diameter at throat x 6 in. to 
 18 in. deep. They can always be considered good 
 property, and when sagged or mis-shaped, or cracked 
 by heat and wear, can be melted down and revivified 
 with a proportion of new metal, and worked up 
 again to their original shape at the cost of very 
 little more than the labour employed. 
 
20 MACHINERY AND APPARATUS 
 
 The manufacture of fine pewter is somewhat of 
 a lost art, and very few persons have a thorough 
 knowledge of it. 
 
 TILTING PANS. 
 
 Steam-jacketed tilting pans are very useful 
 appliances, but are in much more general use for 
 jam making and fruit preserving than for pharma- 
 ceutical purposes. Their greatest utility is for 
 melting substances for subdivision into jars, and 
 for rapidly evaporating small quantities of valuable 
 fluid extracts, which can be emptied out, by tilting, 
 to the last drop, thus insuring no such loss as occurs 
 where baling out is necessary. They are usually of 
 copper, from 5 to 40 gallons content, with a copper 
 light course, having a pouring lip in the front. They 
 can be fitted in cast-iron or copper steam jackets on 
 trunnions, with stuffing boxes for the admission of 
 steam and the eduction of condensed water, the 
 trunnions being mounted on, and working in, bear- 
 ings on columns or frames, and the pans having 
 a tilting lever attached, which can be kept in any 
 desired position by a pin passing through a quad- 
 rant attached to one of the frames. When the pans 
 are of large size and heavy, worm and worm-wheel 
 gear is substituted for the tilting lever. 
 
 STEAM BOILING COILS. 
 
 Liquids can be very efficiently boiled by means of 
 steam enclosed in coils of piping, or by blowing the 
 
FOR MANUFACTURING CHEMISTS 21 
 
 DOUBLE WING COIL FOR BOILING ROUND 
 
22 MACHINERY AND APPARATUS 
 
 steam by a pipe or silent boiling nozzle direct into 
 the liquid to be heated. 
 
 Steam coils are best formed of copper pipe, on 
 account of its great conductivity. They should 
 always be placed right on the bottom of the vessel 
 containing the liquid to be boiled, and be formed in 
 such a manner that the steam has sufficient length 
 of travel or circulation before becoming condensed to 
 enable it efficiently to impart its heat to the liquid. 
 Each steam coil should be connected to a steam 
 trap, to enable the water to be automatically and 
 continuously discharged, so that the coil is kept free 
 from water, and there is consequently no heat lost 
 by too rapid condensation, or by the coil becoming 
 water-logged. 
 
 In calculating the surface required in any coil to 
 boil a given quantity of liquid in a given time, the 
 pressure and consequent temperature of the steam 
 must be taken into consideration, and the requisite 
 number of units of heat per- square foot of surface 
 per hour allowed for, 1 F. difference of internal 
 and external temperature. Roughly, it is usual to 
 allow 4 1 to 6 ft. of heating surface in a steam coil 
 for every 100 gallons in the capacity of the vessel 
 containing the liquid to be boiled. 
 
 Every 10 ft. of heating surface in the coil may be 
 reckoned to require 1 h.p. of steam per hour, 1 
 cubic foot of water evaporated to steam. 
 
 When water is heated by blowing indirect steam, 
 the volume is increased by the steam becoming con- 
 densed that is used in raising the water from its 
 initial temperature to boiling point. The volume 
 is thus usually increased about one-fifth. This is 
 certainly the most economical method of heating 
 
FOR MANUFACTURING CHEMISTS 23 
 
 DOUBLE WING COIL FOR BOILING BACK, WITH MANHOLE. 
 
24 MACHINERY AND APPARATUS 
 
 water by steam, as the whole of the heat in the 
 steam is imparted to the water. 
 
 VACUUM PANS. 
 
 The vacuum pan was invented and patented by 
 Mr. E. C. Howard in 1812, and may be described 
 as a closed vessel in connection with an air-pump 
 for the evaporation of liquids at low temperatures. 
 For ordinary purposes the atmospheric pressure 
 may be taken at 15 Ibs. per square inch, or equal 
 
 to 30 inches of mercury, and at this pressure the 
 boiling point of liquids is constant, but is liable to 
 be affected by change of circumstances, which may 
 .arise from various causes, such as the amount of 
 pressure exerted upon the surface of the liquid, 
 the density of the liquid, the substances held in 
 
FOR MANUFACTURING CHEMISTS 25 
 
 solution in the liquid, i.e. its hygroscopic nature, 
 the nature of the vessel containing the liquid, and 
 the depth of the liquid mass. Boiling water is 
 nearly always of one temperature, because it is ex- 
 posed to a tolerably uniform atmospheric pressure ; 
 but could this pressure be removed the boiling 
 would take place at a considerably lower tempera- 
 ture. Hence the boiling point of a liquid varies 
 with the pressure over its surface ; the greater the 
 pressure the higher the temperature at which it 
 boils, and vice versd. But boiling or ebullition is 
 not necessarily produced by the application of heat, 
 for by simply removing the pressure a liquid pre- 
 viously in a quiescent state may be made to boil. 
 For example : in a close vessel containing a quantity 
 of warm water placed in communication with an 
 air-pump, as exhaustion proceeds, and gradually 
 withdraws the pressure from the surface of the 
 water, the water will commence to boil at a certain 
 point of rarefaction ; but supposing the air pump 
 to stop working, the boiling would soon cease, and 
 for this reason : that the vapour gradually accumu- 
 lates, and having no means of escape, at length 
 exerts a pressure over the water equal to that of 
 the external atmosphere, and hence the boiling will 
 cease. It will thus be seen that were it not for 
 the pressure of the atmosphere it would be difficult, 
 or perhaps impossible, to procure hot water. 
 
 Boiling water, it is true, might at all times be 
 obtained with the greatest facility, but the water 
 in this case would not be hot. That a liquid 
 should boil and not be hot seems to imply a con- 
 tradiction ; but it must be borne in mind that the 
 term boiling is simply the rapid formation of vapour 
 
26 MACHINERY AND APPARATUS 
 
 at all points of a liquid without reference to the 
 degree of temperature. 
 
 Boiling can take place in a vacuum pan as low 
 as at 80 Fahr., with a perfect vacuum. In a 
 vacuum pan each foot of heating surface will 
 evaporate about twice as much water per hour as 
 in an open pan. Vacuum pans are made in copper 
 and in cast and wrought-iron, with steam jackets, 
 and with and without steam coils, and are used 
 principally for boiling and granulating sugars, con- 
 centrating milk, worts, and all products and ex- 
 tracts which require to be evaporated, concentrated, 
 dried, or distilled at low temperatures. 
 
 In an ordinary vacuum pan with jet condenser 
 the vapour is condensed by, and passes through, a 
 wet air-pump with the condensing water. An 
 efficient wet vacuum pump for exhausting a va- 
 cuum pan should have a capacity of 1,900 circular 
 inches of piston displacement per minute per foot 
 of heating surface in the pan. The amount of 
 water required for use in the condenser of a vacuum 
 pan varies with the form of condenser and that of 
 the spraying apparatus. The very best forms re- 
 quire about ten to twelve gallons of water per hour 
 per foot of heating surface in the pan, and inferior 
 forms sixteen to eighteen gallons. 
 
 The best and most economical results are obtained 
 in a Torricellian condenser, through which a much 
 larger amount of water is allowed to fall than is 
 necessary . t for merely condensing the vapour from 
 the pan. This water being collected at the base 
 in the tank and pumped up again, so as to be used 
 over and over again, and in first cost the necessary 
 plant is expensive. In a vacuum pan fitted with a 
 
FOR MANUFACTURING CHEMISTS 27 
 
 Torricellian condenser, the vapour is condensed 
 by injection of water which falls 34 ft., and runs 
 to waste-^the air only being withdrawn at the 
 same time from the top of the condenser by a dry 
 vacuum pump. 
 
 In a vacuum still the vapour is condensed in a 
 closed tubular condenser surrounded by water, and 
 passes into one or more receivers as distillate, the 
 air being withdrawn from the top of the receiver 
 by a dry vacuum pump, and the distillate being 
 preserved or allowed to run to waste as desired. 
 
 Vacuum pans vary in size from a few inches in 
 diameter to 24 ft. in diameter, and from a capacity 
 of 1 gallon to 10,000 gallons. 
 
 To dry glutinous substances in vacuo, or to dry 
 substances containing crystallizable matter, such 
 as malt extract or patent foods, to a friable powder 
 a special form of vacuum pan is required, having a 
 flat bottom with deep sides and dome, the bot- 
 tom and sides being steam-jacketed all over, and 
 being polished inside, and fitted with a close-fitting 
 revolving rousing apparatus, with knife edges, 
 sweeping the whole of the surface so close as to 
 prevent a single grain adhering and getting caked 
 on to the surface the rouser being fitted with 
 cross-blades to break up any lumps and prevent 
 massing or clogging. Any desired temperature can 
 be used in these pans ; and as there is very little 
 moisture in the goods to vaporize, they only require 
 connecting to an ordinary form of condenser, and 
 either a dry or wet vacuum pump, in which a good 
 vacuum can be maintained. It is possible to boil 
 goods in vacuo at 500 F. by using superheated 
 steam, and to boil sugar for manufacturing toffee 
 
28 MACHINERY AND APPARATUS 
 
 or hard crack from a mixture of cane sugar and 
 glucose with ordinary high-pressure steam at 
 temperatures up to 350 F., without any pos- 
 sibility of granulation setting in. Pans for this 
 purpose have a very large amount of both steam 
 jacket and coil surface, with a condenser pipe of a 
 small throttled area, and produce goods of a much 
 more regular consistency and more rapidly than 
 they can be produced at the same temperatures in 
 open sugar-boiling pans over an open fire. This 
 system also obviates the risk of fire, and is much 
 more cleanly than the use of fire heat. 
 
 The most economical results in evaporation in 
 vacuo can be obtained by the multiple effect ap- 
 paratus which is now in common use, and which is 
 composed of a series of vessels, each having a 
 steam chamber from which the vapour rising from 
 evaporation in the first vessel passes away as 
 steam to heat the second, and the vapour or steam 
 produced in the second heats the third, and so on. 
 
 These apparatus are known as double, triple, and 
 quadruple effect, and consist of a series of vessels 
 having tubular steam chambers arranged vertically 
 or horizontally, in which a vacuum is formed and 
 graduated, so that the liquid to be treated is boiled 
 at a constantly low temperature in proportion to 
 its degree of concentration. Exhaust steam from 
 engines and live steam, only when necessary, are 
 generally used in the first vessel ; hence the 
 economy in working, as it will evaporate and con- 
 dense a quantity of water in each vessel nearly 
 equivalent to its own weight. 
 
 There are various patented forms of multiple 
 effect evaporators, but perhaps the most successful 
 
FOR MANUFACTURING CHEMISTS 29 
 
 is that known as the Yaryan, an American inven- 
 tion. This invention relates to an improved evapo- 
 rating and distilling apparatus operated in multiple 
 effects, in which the evaporation takes place while 
 the liquid is flowing through heated coils of pipe 
 or conduits, and in which the vapour is separated 
 from the liquid in a chamber at the discharge end 
 of the coils, and is conducted to the heating cylinder 
 surrounding the evaporating coils of the next effect 
 from the first to the last effect. 
 
 STIRRERS. 
 
 Mechanical stir re rs applied to evaporating pans 
 add very much to the efficiency of the pans, and save 
 an immense amount of labour. There are, however, 
 many practised laboratory hands who declare that 
 there is no better system than hand-stirring with 
 spatulas. 
 
 The simplest and best form of mechanical stirrer 
 consists of a short shaft with socketed end, into 
 which the stirrer blade is fastened by a set screw, or 
 with a plain end with two set screws which fasten 
 the stirrer blades (preferably made of hard wood) at 
 any desired angle, the blades having long slotted 
 holes for the set screws to make them adjustable. 
 
 To the upper end of the shaft a mitre wheel is 
 keyed, driven by another mitre wheel keyed on a 
 short lay shaft, having strap or gut pulleys on to 
 other end. Both the vertical shaft and the lay 
 shaft are fitted in bearings contained in a cast-iron 
 frame bracket, which can be bolted to a wall as a 
 cantilever, or to a beam fixed over the centre of the 
 
30 MACHINERY AND APPARATUS 
 
 pan containing the goods to be stirred, the bearings 
 having loose swivel caps which allow the shaft to 
 be withdrawn immediately when desired. 
 
 For stirring or blending in deep vessels the vertical 
 shaft should be made hollow, and have another one 
 passing through it and projecting below it, each 
 baing fitted with a mitre wheel driven by the mitre 
 wheel on the lay shaft in opposite directions, so that 
 the blades on these shafts pass each other and churn 
 up the goods through which they pass. These can 
 be very easily and cheaply constructed of ordinary 
 wrought-iron steam tubing, with a solid toe-step 
 working in a bearing attached to the top of a vessel. 
 
 BOILING FOUNTAINS. 
 
 This apparatus consists of a copper inverted funnel, 
 having holes at its base, with a vertical pipe and 
 hood, and can be used in any boiling vessel or evapo- 
 rating pan to enable a large quantity of liquid to 
 be heated in the vessel without boiling over. 
 
 The fountain, when placed in a vessel or pan, 
 should practically cover the heating surface, and will 
 cause an upward current of the boiling liquor to 
 enter the cone through the holes, rise through the 
 vertical pipe, strike the hood at top, and return to 
 the pan, thus dissipating great heat in vapour and 
 preventing boiling over. 
 
 Care should bs taken to ensure the steam inlet or 
 inlets into the jacket of the pan in which it is used 
 being directly underneath the cone. The vertical 
 pipe is preferably made telescopic, so that it can be 
 regulated at will to the force of the upward current. 
 
 This simple apparatus will save a considerable 
 
FOR MANUFACTURING CHEMISTS 31 
 
 quantity of fuel, and efficiently aerate the boiling 
 liquor in which it is placed. 
 
 DISTILLATION. 
 
 A still was formerly called in English the stilla- 
 tory, from the Latin word still a, a drop, stillare, to 
 drop ; and retort is from the Latin retortas, past 
 participle of retorquere, to twist back. 
 
 Distillation is the evaporation of a liquid in a close 
 vessel to vapour, the vapour thus evaporated being 
 conducted into a refrigerator, where it is condensed 
 arid liquefied again. 
 
 The boiling points of liquids differ considerably. 
 Water boils at 212 F., and alcohol at 173 F., so that 
 in a mixture of those liquids the alcohol vaporizes 
 first and separates itself from the water ; it, however, 
 does not do so entirely, but carries over with it a 
 quantity of water with which it becomes entangled, 
 and requires to be re-distilled or rectified to become 
 pure. 
 
 Boiling points of liquids at atmospheric pressure 
 are as follows : 
 
 Sulph. ether . . . S '73ti5 100 
 
 Alcohol .... -813 173 
 
 Muriatic acid . . . 1O47 222 
 
 Nitric acid . . . . 116 220 
 
 13 . 240 
 
 Sulphuric acid . . . T85 620 
 
 Oil of turpentine .... 316 
 
 Naphtha 306 
 
 Sulphur 570 
 
 Linseed oil 600 
 
 Mercury 662 
 
 Glycerine ...... 554 
 
 Water 212 
 
32 MACHINERY AND APPARATUS 
 
FOR MANUFACTURING CHEMISTS 33 
 
 Stills for various purposes consequently differ very 
 much in form, but can be divided into two classes 
 the first being for ordinary distillation, and the 
 second for continuous distillation. 
 
 In the first case the still is charged with a given 
 quantity, heat applied, and vaporization and con- 
 densation continued until the charge is entirely 
 evaporated or exhausted of alcohol. In the second 
 case the charge runs continuously into the still 
 during the process of distillation, assisting in its 
 course to condense the spirituous vapour arising, and 
 in its turn giving forth vapour evolved by the heat 
 absorbed by coming in contact with the heated 
 vapours rising from the body of the apparatus. 
 
 Spirit is distilled from fermented wash made by 
 the infusion of malted and unmalted grain, sugar, 
 molasses, wines, wine lees, fruit, flowers and seeds 
 and aromatic plants. 
 
 Destructive distillation is the decomposition of a 
 substance in a close vessel in such a manner as to 
 obtain liquid products. 
 
 By a product is meant a body not originally pre- 
 sent in the substance distilled. A body merely 
 extracted without change by distillation is termed 
 an educt. Manufactured ozokerite consists in part 
 of educts from the native mineral ; but this is a 
 singular case in the industry of destructive distilla- 
 tion. 
 
 The apparatus employed in destructive distillation 
 consists essentially of a retort followed by a con- 
 denser and a receiver. The substance to be operated 
 on is placed inside the retort, to which heat is ap- 
 plied. The volatile products pass over and are 
 condensed in long straight or vertical tubes, which 
 
34 MACHINERY AND APPARATUS 
 
 are kept more or less cooled. The average contrac- 
 tion from heated vapour to liquid may be taken at 
 about 1,000 to 1. The retorts or stills are of various 
 forms, and either horizontal or vertical, and are 
 made of glass, iron, clay or brick. Heat is applied 
 directly either to sides or bottom, or both, and 
 superheated steam -alone may be driven in at one 
 end. Steam of varied temperature and direct heat 
 are sometimes used together. 
 
 The nature of the product depends mostly on the 
 composition of the substance heated and the degree 
 of heat applied. 
 
 The retort was, doubtless, originally derived from 
 the clay bottle, which in its turn was modelled on 
 an animal skin or vegetable seed case. 
 
 In the sixteenth and seventeenth centuries destruc- 
 tive distillation came to be the principal work in 
 chemical laboratories. Most animal substances, 
 sometimes the whole body, such as that of the 
 viper, also plants, were examined or analysed ; but 
 seldom any detailed investigation was made of the 
 products. 
 
 ESSENTIAL OIL DISTILLATION. 
 
 Essential oils exist in most aromatic plants in their 
 different organs, more particularly in their leaves, 
 flowers or fruits, and most give their largest yield 
 when dealt with in a fresh state. Most of them can 
 be extracted by distillation in stills worked by fire 
 or steam, preferably the latter, fitted with a perfo- 
 rated false bottom to prevent the matter adhering 
 to the bottom of the still. The distillate must be 
 
FOR MANUFACTURING CHEMISTS 35 
 
 caught in a separator, in which the oil is separated 
 from the water. 
 
 Various forms of stills can be used for this purpose. 
 The matter should be placed in the still with water 
 in which it has been macerated. Salt is sometimes 
 added to retard the point of boiling to about 229 F., 
 particularly when the oil is heavy, as it separates 
 easier if distilled above 212 F., but it sometimes 
 injures the distillate. 
 
 When distilling crystallizable oils, such as aniseed, 
 caraway, peppermint, fennel or roses, care should 
 be taken to keep the condenser rather warm about 
 115F. and in some cases the condenser should 
 command the still, so that the watery portion of the 
 distillate, or mother liquor, can be continuously 
 passed back from the separator to the still until it 
 is exhausted of oil, when it will run out in a limpid 
 form and loses its milky appearance. 
 
 Among the number of essential oils that are 
 distilled may be mentioned bay, camomile, cloves, 
 cubebs, dill, eucalyptus, geranium, lavender, neroly- 
 bigarade, orange-flower water, otto of roses, oil of 
 orris, pimento, peppermint, rosemary, thyme, spike- 
 lavender. Essential oils heavier than water at 15 
 C. = 59F. are cassia, 1-060 sp. gr. ; cinnamon, 1 '030 ; 
 clove, 1-050 ; and those lighter than water, bay, -990; 
 bergamot, '885 ; caraway, '925 ; camomile, *910 ; 
 citronella, -887; copaiba, -900; cubeb, -925; dill, 
 914 ; pine, -870 ; and rosemary, -900. 
 
36 MACHINERY AND APPARATUS 
 
 ALCOHOL STILLS. 
 
 What the manufacturing chemist knows as an 
 alcohol still is any still in which he can recover 
 spirit from marcs or rectify any spirit which has 
 become dirty and weakened by use in percolation 
 or washing processes. In mixing alcohol with water 
 it must be remembered that equal quantities of each 
 contract in bulk nearly 4 per cent., i.e. 100 c.c. of 
 alcohol and 100 c.c. of water contract to 192*8 c.c. 
 when mixed. 
 
 Perhaps the most useful pattern is the French 
 one, consisting of a copper steam jacketed still, 
 flanged at top and surmounted by a turk's cap still- 
 head connected to the worm by a tapering vapour- 
 conducting pipe, bent to a large radius, and conse- 
 quently standing some considerable height above 
 the still, thus ensuring clean spirit ; the worm 
 usually has a vapour globe at top, which effects 
 a steady flow of distillate and is contained in an 
 ordinary copper or galvanized iron worm tank. 
 
 The Excise will not permit any apparatus to be 
 used for recovering methylated spirit from marcs, 
 etc., which rectifies the spirit so as to increase its 
 strength. 
 
 ALMOND OIL STILLS. 
 
 The best form of still for extracting almond oil is 
 made of copper, of elliptical form, fitted in a steam 
 jacket, surmounted by a pewter still-head, having 
 a stuffing box in its centre at top, through which 
 works the shaft of a cross-bladed rouser, cut to the 
 
MANUFACTURING CHEMISTS 37 
 
 shape of the still and actuated by a handwheel or 
 a gut-driven wheel keyed to the shaft outside the 
 stuffing box. 
 
 The worm should be pewter, arranged as a Liebig 
 condenser or as an ordinary worm in a tub, the dis- 
 tillate being caught in a separator and afterwards 
 strained through muslin or filter paper before 
 storing. 
 
 PORTABLE STILLS. 
 
 Portable stills consist of complete distilling ap- 
 paratus which can readily be removed en ~bloc and 
 set to work without fixing. They are best under- 
 stood as copper stills, tinned inside, fitted in wrought 
 iron furnace frame on feet, with fire door, and ashpit 
 
38 MACHINERY AND APPARATUS 
 
 cloor, and smoke stack pipe. A copper globular still- 
 head with pure tin lower end and worm in worm- 
 tub, mounted on a wooden stand. They are used 
 principally for experiments or distilling essences 
 and for water distilling in small quantities. They 
 are sometimes fitted with copper tubular rectifying 
 heads to produce strong spirits, but the application 
 of rectifying apparatus on such a small scale hardly 
 warrants the expense. 
 
 In France and Italy all forms of distilling appa- 
 ratus will be found mounted on wheels for removal 
 from place to place for brandy distilling from wine 
 lees, grape cake or fruit, where the vineyards lie 
 far apart. 
 
 MINT STILLS. 
 
 Mint or peppermint is of two varieties, white and 
 black. The white yields the finest oil but the black 
 yields a larger quantity. It is grown in various 
 parts of England : in Surrey, Sussex, Kent, Cam- 
 bridgeshire, Lincolnshire and Hertfordshire ; but the 
 best comes from Mitcham, in Surrey, grown in light, 
 chalky soil. An average crop is two tons to the 
 acre, yielding about 10 Ibs. of oil to the ton. 
 
 It is distilled in either steam or fire stills, but 
 generally in fire stills made of copper, with copper 
 still-heads and pewter worms in wood tubs. The 
 distillate runs into a separator, where it is separated 
 from the water and afterwards filtered. 
 
 A 1,2CO gallon still will take a charge of 1 ton of herbs. 
 A 9CO 15cwt. 
 
 A GOO 10 
 
FOR MANUFACTURING CHEMISTS 39 
 
 The process is usually conducted in the most 
 primitive, wasteful manner, the mother liquor being 
 usually allowed to run to waste from the separator 
 instead of being returned to the still while working 
 or reserved for wetting the next charge ; and there 
 is no doubt a large percentage of the oil goes there- 
 fore down the drain. 
 
 ACETIC ACID STILLS. 
 
 Acetic acid is the sour principle of vinegar. Com- 
 mercial acetic acid is met with under the forms of 
 pure glacial and dilute acids, and of vinegar of 
 many varieties. It is obtained from fermented 
 liquors, vinegar, alcohol and wood by distillation as 
 pyroligneous acid, and the commercial acetates of 
 soda, potassium, lime, lead, copper, etc. The acetates 
 acted on by strong acids liberate the acetic acid, or 
 by distillation in vapour by heat. 
 
 Acetic acid is obtained from wood by destructive 
 distillation, and is known as pyroligneous acid or 
 crude acetic. It is distilled in closed iron retorts, 
 and comes over as distillate with tar, creasote, wood 
 spirit, and other liquids and gaseous matters, leaving 
 charcoal as a residuum. 
 
 In this state it contains much empyreumatic 
 matter in solution ; by separation from the tar and 
 saturation with chalk or slaked lime, defecation, 
 and evaporation, an impure acid is obtained, which, 
 after being gently heated, to destroy some of the 
 empyreumatic matter without injuring the acid, 
 it is again dissolved, defecated, and precipitated by 
 a solution of sulphate of soda, when a solution of 
 
40 MACHINERY AND APPARATUS 
 
 acetate of soda and a precipitate of sulphate of lime 
 are formed by double decomposition. The solution 
 is then evaporated to dryness and dissolved in water, 
 then filtered and crystallized. The crystals of acetate 
 of soda obtained yield nearly pure acetic acid by 
 distillation with sulphuric or hydrochloric acids. 
 One ton of oak is said to produce about 1,300 Ibs. 
 of acid and 600 Ibs. of charcoal. 
 
 The cylindrical iron retorts are usually built in 
 brickwork in sets of eight or less, with oven below 
 for drying the acetate of lime ; they vary from 2 
 feet 6 inches diameter to 4 feet, and from 4 to 
 10 feet long, and the smaller they are in diameter 
 the more rapid the distillation. The wood is cut up 
 and packed into the retorts as closely as possible, the 
 average charge for each retort being about 24 cwt. 
 One end of the retort is fitted with a hinged door, 
 and the other end has a pipe leading away to the 
 condensers, formed of pipes surrounded by water. 
 The mixed distillates run from the condensers to 
 the settling backs, which are usually made of wood. 
 The tar falls to the bottom and is drawn off to a 
 tar still, and the remainder is treated in various 
 ways to produce naphtha or acid, by slow distillation 
 to separate the naphtha either before or after the 
 acid is neutralized by lime. 
 
 For producing pure rectified acetic acid the ace- 
 tate of soda is placed in copper steam-jacketed stills 
 covered by a stone luted on. Hydrochloric or sul- 
 phuric acid is added or fed in gradually, and the heat 
 being applied, the vapour rises through an earthen- 
 ware or pure tin still-head, and is condensed in a pure 
 tin worm contained in a tank of water. The head 
 is best attached to the worm by a water-seal joint 
 
FOR MANUFACTURING CHEMISTS 41 
 
 which is instantly removable, and prevents possible 
 leakage. Stills vary in size from 50 to 300 gallons 
 content. After distillation, the soda is dug out of 
 the still and the still re-charged with grey or brown 
 acetate of soda. 
 
 The copper pans of these stills should be consider- 
 ably thicker than those for other purposes, and 
 never less than f inch thick, not only to resist the 
 action of the acid, but to stand the wear and tear of 
 the cutting they are exposed to from the edges 
 of the shovels in digging out the soda. 
 
 THE AUTO STILL. 
 
 This apparatus was designed by the author to 
 supply a want long felt by chemists, dispensers, 
 wine merchants, hotel keepers, analysts, and hos- 
 
42 MACHINERY AND APPARATUS 
 
 pitals, etc., i.e. the production of sufficient pure 
 distilled water for their daily need, automatically, 
 in an inexpensive apparatus, requiring no attention, 
 at the lowest possible cost. 
 
 Even chemists who are supplied free with distilled 
 water by wholesale houses, but have to pay for the 
 carriage of it, will find the use of this apparatus 
 economical. 
 
 It consists of a copper still, 2 gallons content, 
 tinned inside and fitted with draw-off cock mounted 
 on a low pressure atmospheric gas heater. The still 
 is connected to a pure tin condensing worm in tank 
 by a pure tin swan neck fitted with unions, and 
 between the still and worm tank is a water regu- 
 lating cistern, the whole being mounted on a cast- 
 iron bedplate 2 feet long by 8^ inches wide. The 
 apparatus simply requires connecting by india- 
 rubber tubes to the gas and water main. The 
 water enters the regulating cistern 'and passes by a 
 pipe to the bottom of the worm tank, overflows 
 warm from the worm tank into the still, in which 
 it is heated and vaporized ; and as each particle is 
 condensed into distillate, so is an equally propor- 
 tionate amount fed automatically into the worm- 
 tank and thence into the still. 
 
 A gallon of boiling water may be drawn from the 
 still without disturbing the flow of distillate. An 
 oil lamp can be used instead of gas if required. 
 
 This apparatus produces about half a gallon of 
 distillate per hour, or, say, 4 gallons per day. 
 
FOR MANUFACTURING CHEMISTS 
 
 43 
 
 EARTHENWARE STILLS. 
 
 Earthenware stills are used in laboratories for the 
 production of spirits of nitre, sal volatile, prussic 
 acid, and for rectifying ammonia, etc., and vary in 
 capacity from 5 to 30 gallons. 
 
 The still should be provided with a thermometer 
 passing through an india-rubber cork fitting in a 
 tubulare on the breast of the still, and should be 
 fitted in a cast-iron steam jacket, having its steam 
 joint made with india-rubber rings above and be- 
 low the earthenware flange, compressed into a recess 
 cast in the jacket by a wrought-iron jointing ring 
 with studs and gun-metal ring fly-nuts, which ar- 
 rangement allows sufncient expansion, and by which, 
 
44 MACHINERY AND APPARATUS 
 
 in case of fracture, a new still can be jointed in in 
 a few minutes. The jacket should be mounted on 
 legs, and fitted with steam, air, and condensed water 
 cocks and a safety valve, a guard plate being fitted 
 inside the jacket over the steam inlet to distribute 
 the steam and prevent it impinging directly on to 
 one portion of the earthenware still. 
 
 The head should be luted on to the still and kept 
 safe by a wrought-iron tripod bridle stay, which 
 fastens on to three of the studs in the joint of the 
 jacket ; the dip arm and elbow to the worm should 
 also have their luted joints bound or clipped to- 
 gether. 
 
 The worm should be contained in a galvanized 
 iron worm tank having its outlet pipe passing 
 through a gun-metal stuffing box and gland packed 
 with asbestos yarn to allow of expansion, the stuff- 
 ing box being bolted to the side of the tank. 
 
 The worm tank should be mounted on a con- 
 venient iron stand and be fitted with water inlet 
 cock and copper overflow pipe, washer, and waste for 
 cleaning it. 
 
 CARRAWAY OIL STILLS. 
 
 The best form of still for extracting oil from 
 carraway seeds is a shallow copper still steam- 
 jacketed at the bottom only, and mounted on 
 columns. It should be of, say, 300 gallons capacity, 
 with a proportionate depth to its diameter, as 1 is to 
 3. The bottom pan or heating surface should be 
 shallow say 8 inches deep, with a flanged light 
 course about 12 inches deep surmounting it. The 
 
FOR MANUFACTURING CHEMISTS 45 
 
 dome should be connected to this by quick releasing 
 fastenings, *and be fitted with chains and balance 
 weights to enable it to be swung up and suspended 
 above the still when it is necessary to discharge the 
 spent seed. 
 
 The still should have close and free steam con- 
 nections, so that either system can be used at 
 pleasure. 
 
 A tinned copper wire-work grating is often fitted 
 in the still, on which the seeds are charged, and free 
 steam blown through, carrying with it the oil into 
 the still-head, which should be of pewter, and thence 
 into a pewter condenser, of the Liebig type in pre- 
 ference, from whence it passes as distillate to the 
 separator, where the oil is separated from the water. 
 
 As this oil is of a crystallizable nature, the con- 
 denser should be kept at a temperature of about 95 
 F. When close or jacket steam only is used, the 
 still should be fitted with horizontal paddle-bladed 
 rousers attached to a shaft working in a stuffing 
 box fitted in the light course and actuated by gear- 
 ing externally. The temperature in the still for 
 heavy oils should not be less than 212 F., and as 
 sometimes salt is used to retard the boiling point, it 
 is necessary to increase the heat to 230 F. 
 
 Clove oil is distilled from cloves in a similar form 
 of still to that described for carraway seed, but it 
 should have a proportionate depth to its diameter, 
 as 2 : 3. 
 
 BALNEUM STILLS. 
 
 Balneum or water bath stills are extremely useful 
 for distilling from delicate substances which de- 
 
46 MACHINERY AND APPARATUS 
 
FOR MANUFACTURING CHEMISTS 47 
 
 teriorate under fire or steam heat, particularly when 
 they are very thick, but they are not to be recom- 
 mended for distilling or rectifying alcohol in any 
 form, as there is a loss of aroma as compared to that 
 distilled by a fierce heat, as well as an imperfect 
 exhaustion of alcohol from the liquor being distilled. 
 The balneum is a vessel which fits into a still and 
 is surrounded by the water in the still, which, when 
 heated, imparts its heat in a modified form to the 
 contents of the balneum. 
 
 When it is necessary to distil alkaloid substances 
 in pure tin, a balneum will be found very useful, as 
 pure tin will not stand direct heat without sagging 
 and going out of shape. 
 
 Small copper water bath stills for pharmaceutical 
 uses, constructed so that they can be used either 
 with or without a water bath, or as an evaporating 
 pan in a water bath, or as an evaporating pan with 
 direct fire or gas heat, having a removable dome 
 fitting in a water seat round the pan, to which 
 the still-head is attached by a union joint, cannot 
 be over- valued in their general utility ; they are in 
 much commoner use in France than in England. 
 
 VACUUM STILLS. 
 
 A vacuum still is the greatest desideratum in a 
 laboratory, and yet it is rarely met with. It can be 
 used for ordinary atmospheric distillation and dis- 
 tillation in vacuo, for atmospheric concentration and 
 concentration in vacuo, for drying delicate goods 
 without change of colour in the smallest quantities 
 
48 MACHINERY AND APPARATUS 
 
 at low temperatures, and for recovering spirit 
 rapidly from marcs without the slightest loss. 
 
 It has already been generally described under the 
 head of vacuum pans. Where more than one distil- 
 late receiver is used the process becomes a continuous 
 one, for as one fills, the pump suction and distillate 
 cocks are shut off from it and those on the next 
 receiver opened. The vacuum is then broken in 
 the first receiver and the contents can be drawn off, 
 after which it can be again put into use as soon 
 as the second receiver requires discharging and 
 a change once takes place. When concentration 
 is taking place and the distillate is merely water, it 
 can be run to waste; but when the distillate has any 
 spirituous value, every particle of it can be saved. 
 
 Dry vacuum pumps can now be applied to such 
 apparatus capable of maintaining a vacuum to 
 within 1,000th part of a millimetre of a perfect 
 vacuum, equivalent to the state of the barometer. 
 Such pumps have their piston and valves per- 
 petually sealed by suitable liquids, and are so 
 constructed as to cause the air, instead of being 
 drawn through the piston, to be lifted above it 
 and discharged through the delivery valve. Thus 
 no air can possibly return through the pump. 
 
 WATER DISTILLING. 
 
 Distilled water must not be confounded with con- 
 densed water. A very large number of manufactur- 
 ing chemists content themselves with collecting the 
 condensed water resulting from the use of steam in 
 steam jackets, coils, etc., and not only use it them- 
 
FOR MANUFACTURING CHEMISTS 49 
 
 selves in the place of the pure article, but even sell 
 it as aqua destil., and are often prepared to argue 
 that it is unequalled in purity. 
 
 Pure distilled water can only be condensed in 
 pure tin worms or condensers practically free from 
 solid matter or metallic influence, but very rarely 
 free from ammonia ; and to insure freedom from 
 ammonia a little dilute sulphuric acid must be 
 added to the water in the still. 
 
 The danger in using condensed water as distilled 
 water lies in the fact that the boiler from which the 
 steam is condensed in nearly all cases supplies some 
 form of engine also, and consequently gets some 
 form of impurity carried back into it, such as grease, 
 oil lubricant or chemical matter, which is carried 
 over again with the steam and is very 'difficult to 
 eliminate. 
 
 For distilling small quantities there is no better 
 nor efficient apparatus than the auto still already 
 described or the simple portable still ; but where a 
 large quantity is required the apparatus must take 
 a different form. 
 
 The still should be of copper, tinned inside and 
 heated by a steam jacket, a steam coil, or by fire 
 heat, and be fitted with a discharge cock, a large 
 manhole, a vacuum valve, a set of gauge glass 
 fittings, and a syphon charging pipe and self-regu- 
 lating feed tank, so that as each drop of water is 
 evaporated to steam it is replaced by another, and 
 therefore the water always remains at the same 
 level in the still. This system of feeding increases 
 the output quite 50 per cent, per diem, and causes 
 the apparatus to work safely without any special 
 apparatus. Between the still-body and the still- 
 
 D 
 
50 MACHINERY AND APPARATUS 
 
 head should be bolted in a perforated tinned copper 
 plate, having -inch holes, J-inch pitch, which separ- 
 ate the vapour and add to its velocity, consequently 
 increasing the output, and at the same time serving 
 to throw down the heavy portions and thus insuring 
 greater purity. 
 
 The head should be of the globular or Turk's cap 
 form of large area to allow the vapours ample room 
 to rotate and separate before passing to the con- 
 denser, which can be of any convenient form, but 
 must be essentially of pure English block tin. Such 
 stills should contain about 1J ft. of cooling surface 
 to 1 ft. of heating surface, and be formed so that 
 free access can be given to any portion of the ap- 
 paratus for the purposes of cleaning. 
 
 Any ordinary portable still will produce its con- 
 tent in distilled water in 8 hours, and generally 
 twice this quantity if automatically fed, as the 
 volume of vapour is maintained continuously with- 
 out any perceptible check in temperature. 
 
 CONDENSERS. 
 
 Condensing apparatus for stills is made in several 
 forms. The common form is a circular or oblong 
 worm of copper. Pewter or pure tin, iron, lead or 
 earthenware are fixed in tubs or tanks, in which 
 cold water is allowed to circulate and overflow when 
 heated from the top. 
 
 The Liebig condenser consists of straight con- 
 tinuous tubes enclosed in pipe casings, and generally 
 arranged in sets connected by semicircular bends at 
 the ends, with a gradual fall to the outlet. They are 
 
FOR MANUFACTURING CHEMISTS 51 
 
52 MACHINERY AND APPARATUS 
 
 very convenient for fixing to a wall, and have the 
 advantage of occupying very little space, using less 
 water than worms in tanks and being easily ar- 
 ranged to command the stills, as in the case of 
 essential oil stills, where it is necessary to return 
 the distillate, when the oil is separated from it, back 
 to the still while working. 
 
 The multitubular condenser consists of a number 
 of straight tubes fixed in top and bottom tube 
 plates, contained in an outside casing, in which as 
 little space is left as possible, so as to obtain all the 
 advantages of film condensation. They occupy very 
 little space, use only half the amount of water of other 
 forms, and are practically everlasting, as the tubes, 
 never having been bent, are not strained and retain 
 their true form and hardness. 
 
 The condensing water enters at the bottom and 
 overflows at the top, and can be arranged to pass 
 through the tubes or through the casing as desired, 
 the casing being fitted in either case with a series of 
 semicircular baffle plates dodged to baffle the course 
 of the vapour or water, as the case may be, in its 
 descension or ascension through the condenser. 
 When the vapour goes through the tubes the con- 
 denser is fitted with a cover, which can be readily 
 removed and allows of the tubes being brushed 
 through or examined for cleanliness, a light being 
 placed through the distillate pipe under the bottom 
 tube plate. 
 
 Length of tube, or travel as it is called, is the 
 great desideratum in the design of any condenser, 
 and the tubes of any multitubular condenser should 
 never be less than 5 ft. long. 
 
FOR MANUFACTURING CHEMISTS 
 
 SANDAL-WOOD OIL DISTILLERIES. 
 
 Sandal-wood grows in India and West Australia 
 principally, and is very valuable on account of the 
 oil it contains, which is largely used medicinally, 
 and for perfuming soap, etc. 
 
 The Indian wood yields more oil and of a better 
 quality than the Australian, but it is of a darker 
 colour than the latter, which is nearly white. 
 The extraction of the oil necessitates expensive 
 plant, and requires great care and attention. The 
 wood is first sawn into logs of suitable length, and 
 then fed into a chipping machine, which consists of 
 a quickly running disc fitted with knives like plane 
 irons set at an angle. The disc is mounted on a 
 spindle running in anti-friction bearings on a table, 
 which spindle is fitted with a heavy flywheel and 
 fast and loose pulleys for strap-driving. The ma- 
 chine having been set in motion, the logs are pressed 
 against the cutting wheel by a sliding fence worked 
 by a treadle, and quickly converted into chips. The 
 chips are then fed though a disintegrator, driven at 
 a high speed and mounted on a closed bin fitted 
 with a dust balloon. 
 
 Then comes distillation, which is effected in a 
 steam still of special form. 
 
 The stills are usually from 600 to 900 gallons 
 content, and are made of copper from 6 ft. to 7 ft. 
 6 in. diameter, fitted in cast-iron steam jackets 
 mounted on columns, to work at say 25 Ibs. pressure 
 of steam per square inch. They are fitted with the 
 usual steam fittings, including a safety valve, and a 
 very large discharge cock to discharge the spent wood. 
 
54 MACHINERY AND APPARATUS 
 
 A manhole with cover, crossbar, and screw, large 
 enough for a man to get into easily, should be fixed 
 on the top of the still, and a detachable f\J-shaped 
 syphon pipe on to the side, through which the 
 mother liquor is returned into the still. 
 
 A strong gunmetal cross-blade rouser should be 
 fixed on shaft working in a stuffing box on centre of 
 top of still, and having a toe step bearing over dis- 
 charge hole at bottom, and driven by overhead 
 revolving gearing. The bottom blade should be 
 shaped to the bottom of still, and suspended about 
 1 ft. from the centre, and should be made of special 
 acid-proof metal, and of strong form. 
 
 The vapour outlet should rise from the dome as 
 close to the centre as possible, and be fitted with a 
 taper copper still head 3 to 4 ft. high, surmounted by 
 a pewter swan-neck, connected to a Liebig pewter 
 tapering condenser in cast-iron pipe casings of large 
 area, these casings being arranged with water inlet 
 and outlet connections, and easy means of extract- 
 ing the sludge. The whole of the condenser must 
 command the still breast, so that the distillate can 
 run into a separator or florentine receiver where the 
 oil separates from the water and is skimmed off, the 
 water or mother liquor being returned continuously 
 to the still, through the syphon pipe before men- 
 tioned, until the distillate is quite free from oil, when 
 it is allowed to run into a tank instead, for recharg- 
 ing the still. 
 
 About 5 to 8 cwt. of wood is the usual charge for 
 a still, made up with mother liquor, which requires 
 to be worked continuously for 3 days and nights 
 to complete the operation. 
 
 The yield varies from 1 to 3 per cent, of oil in 
 
FOR MANUFACTURING CHEMISTS 55 
 
 weight as compared to the weight of wood charged, 
 according to the quality of wood, and the skill of the 
 attendant. The oil is then filtered and packed in 
 special bottles for sale. 
 
 SEPARATORS. 
 
 Separators, or florentine receivers, are used for 
 collecting the distillates of essential oil distillations 
 to allow the oil to become separated from the dis- 
 tilled water or mother liquor, on account of the 
 difference in density of the two bodies. They can 
 be made of copper, pure tin, earthenware or glass, 
 and fitted with covers and perforated straining 
 plates, or a loose plate having a pipe attached to 
 its centre with its end bent upwards, which hangs 
 vertically in the separator and allows the distillate 
 to be discharged quietly into the contents without 
 splashing, so that accordingly as the oil is lighter or 
 heavier than the water it ascends to the top or 
 descends to the bottom. 
 
 The separator should be fitted with a swan-neck 
 pipe at the side to discharge the mother liquor, 
 having cocks to connect it to the top or bottom, so 
 that if a light oil is collecting in the separator the 
 bottom cock can be opened to discharge the mother 
 liquor, and if a heavy oil the top one. Distillate 
 containing oil has a milky appearance, which con- 
 tinues until it is practically exhausted of oil, so that 
 directly it runs bright, further distillation is useless. 
 When a sufficient quantity of oil has accumulated in 
 the separator, it is usually drawn off by sampling 
 cocks or skimmed off and filtered. 
 
56 MACHINERY AND APPARATUS 
 
 RECEIVERS. 
 
 Spirit receivers should be made of copper, tinned 
 inside and riveted together with hinged copper 
 manhole covers at top with water seal joints, strap 
 and padlock. They should be fitted with a vacuum 
 and air valve combined at top, and a set of gauge 
 glass fittings with graduated scale and suitable lock- 
 up discharge valves. They should be oblong in form 
 for vessels of from 100 to 500 gallons content, and 
 circular for smaller sizes. 
 
 Open receivers can be of copper or of earthenware, 
 and are in either case best covered with wickerwork. 
 
 DRUG MILLS. 
 
 The most generally useful form of drug-grinding 
 mill is undoubtedly the edge runner mill, although 
 disintegrators are now largely used for almost every 
 form of grinding ; but their product is not so evenly 
 satisfactory as that of the edge runner mill, and 
 in fact it is better to use a disintegrator for coarse 
 grinding, to be finished in an edge runner mill, 
 than to attempt to grind direct in a disintegrator to 
 impalpable powder. Edge runner mills for drug^ 
 grinding, have stones varying from 3 ft. to 8 ft. 
 in diameter and can be arranged so as to be driven 
 from above or below. The stones should be made 
 of the best granite, revolving on a granite bedstone, 
 bedded on a concrete foundation, and surrounded by 
 an iron curb lined with hard wood, and having 
 an opening with sliding door and spout for empty- 
 ing. 
 
FOR MANUFACTURING CHEMISTS 
 
 57 
 
 The horizontal shaft works in bushes fixed in 
 the centre of the stones, having receptacles for oil 
 for self-lubrication, and passes through the navel 
 of the vertical shaft in a bush which moves up and 
 down to suit the irregular path of the stones. The 
 vertical shaft should be fitted with ploughs and 
 sweepers of wrought iron, arranged for throwing 
 in and out of gear by levers. 
 
 3 ft. edge runners will grind about 12 cwt. per 
 day of soft drugs with 8 ft. faces on bedstone. 
 
 3 ft. 6 in. diameter 
 
 4 
 
 5 
 
 6 , 
 
 7 
 
 8 
 
 1 ton 
 
 2 tons 
 4 
 
 8 ! 
 
 9 faces 
 10 
 10 
 12 
 16 
 
 4 ft. in, 
 
 4 6 
 
 5 
 5 6 
 
58 MACHINERY AND APPARATUS 
 
 A very good form of finishing edge runner mill 
 has stones 2 ft. 6 in. diameter, with 6 in. faces 
 running say 30 revolutions per minute on a bed- 
 stone 4 ft. diameter. This is specially suitable 
 for finishing goods after they have been through 
 a disintegrator. Carr's patent laboratory mill, 
 with Minton ware pan and runner, has immense 
 frictional power for levigating purposes and for 
 grinding salts, etc., in small quantities. Both the 
 pan and runner revolve, but the runner is driven 
 at a much greater speed than the pan, and an 
 arrangement is provided by means of which the 
 pan can be tilted over to empty it. 
 
 The hand mill known as the universal drug mill, 
 with helically grooved and fluted rollers, is invalu- 
 able for soft seeds, roots, herbs, etc., and is much 
 used in France. It is provided with combs for keep- 
 ing the rolls free from clogging, and is generally 
 well suited for the everyday wants of pharmacy. 
 
 DISINTEGRATORS. 
 
 Disintegrators are largely used for grinding by 
 percussion or by friction between two corrugated 
 surfaces, but those working on the percussion 
 system, although they require to be driven at 
 higher speeds, are superior, as they actually pul- 
 verize instead of merely granulate the substance to 
 be ground, and do not set up so much friction. 
 The material to be ground can be fed into the 
 machine by a self-acting arrangement, and falls on 
 to the extremity of the beaters, and is beaten by 
 them at a great speed and consequent force against 
 
FOR MANUFACTURING CHEMISTS 59 
 
 a series of screens lining the machine, so. that it 
 becomes pulverized to the mesh of the screen used. 
 
 They are usually made in six sizes, to crush from 
 3 to 30 cwt. per hour, and are driven at speeds from 
 5,000 to 1,000 revolutions per minute. They should 
 be fixed on top of strong, air-tight, wooden bins, 
 provided with dust balloons, which act as air vessels 
 and prevent clogging. 
 
 MACERATORS. 
 
 Substances, previously either cut to pieces, incised, 
 rasped, ground or crushed, according to their nature, 
 are placed in water of ordinary temperature for 
 maceration. 
 
 The proportion of water is usually 3 or 4 times 
 the weight of the substance, and the length of time 
 allowed for soaking is from 12 to 48 hours, according 
 to the dryness or texture of the substance. Vessels 
 for macerating, preparing, diluting or steeping, are 
 made of iron, copper or wood, and are fitted with 
 revolving rakes driven by gearing from the top, 
 which can be worked by hand or power. 
 
 Perhaps the most useful form of macerating 
 vessel for a laboratory is a wooden vat fitted with 
 clip tightening hoops of metal, a perforated false 
 bottom, and a tinned copper steam heating or boil- 
 ing coil fitted underneath the false bottom, and a 
 strainer and draw-off cock. 
 
 This can be placed overhead, so as to command 
 the evaporating pans. 
 
 Infusions can be quickly made by drawing the 
 liquor through a series of close vessels containing 
 
60 MACHINERY AND APPARATUS 
 
 the goods between strainer plates from one to the 
 other by means of a vacuum, and so arranged that 
 each vessel can be separated, and discharged or 
 refilled at plejisure. 
 
 It is a great waste of time and space to macerate 
 in open steam evaporating pans, as is the practice 
 in many laboratories. It will be found much more 
 economical to use portable copper steam jacketed 
 percolators, which can be connected to the steam 
 main by a flexible tube, and which can be arranged 
 to command the pans, so that the infusions can 
 be run off into them for concentration as soon 
 as they are made, and the percolator recharged, so 
 that maceration and concentration can proceed at 
 the same time in a limited space. 
 
 DIGESTERS. 
 
 Digesters for pharmaceutical work might be 
 much more generally and advantageously used 
 than they are, for making extracts and infusions, 
 for sterilizing and producing chemical reactions. 
 Papin's digester is a close vessel with a removable 
 cover, which can be heated over a furnace or by 
 steam, for cooking under pressure or for sterilization, 
 the goods to be operated upon being suspended 
 in it in movable baskets fitted with thermometers 
 to guide the regulation of temperature. 
 
 The more modern form of digesters consists of a 
 jacketed vessel. Steam being admitted to the jacket 
 at high pressure, causes exhaustion or digestion 
 to take place in the vessel, which is fitted with a 
 hinged screw cover, at high temperatures ensuring 
 
FOR MANUFACTURING CHEMISTS 61 
 
 rapid and thorough, extraction. Bone essences and 
 marrows can thus be entirely extracted, leaving 
 the bone in a calcined state. Essences made in 
 this way are placed in jars inside the digester, 
 and lose none of their aroma or nutritious proper- 
 ties while cooking. Extractions from roots, herbs 
 or barks can be readily effected, by placing them 
 in the vessel with sufficient water to absorb the 
 extract. Meat can easily be cooked in them by 
 suspending it inside the vessel without adding 
 water, its own juices being found sufficient moisture 
 to assist in the cooking. Meat treated in this 
 manner becomes thoroughly cooked and very ten- 
 der, and by shutting off the steam from the jacket, 
 and turning cold water in suddenly, all the gravy 
 becomes condensed on the meat and it loses nothing 
 in weight. 
 
 COOKING BOILERS. 
 
 Cooking boilers, for heating liquids or for mak- 
 ing caramel, or dissolving any solid mucilaginous 
 substances, are usually made of copper, wrought 
 iron or galvanized iron, mounted in iron furnace 
 frames, and arranged for tilting. They are heated 
 by fire or gas, and are sometimes fitted with false 
 bottoms to prevent burning. Caramel pans or 
 boilers should be fitted with telescopic suspended 
 hoods, to enable the vapours to be passed away^ 
 into a flue. It has been found that handstirring 
 is much more effective for caramel-making than 
 any mechanical contrivance. 
 
62 MACHINERY AND APPARATUS 
 
 EXTRACTION OF DYE FROM WOODS. 
 
 The wood must be first reduced to powder or 
 chips in a chipping machine or disintegrator, or 
 sawn into small pieces, and it then goes through 
 the process of curing or fermentation. 
 
 This consists in moistening it with water and 
 piling it in heaps not more than 3 ft. in depth, 
 from 4 to 6 weeks exposed to the air. It should be 
 turned at intervals to regulate the temperature and 
 allow contact with the air. More water should then 
 be added, and the process continued until it assumes 
 a rich, reddish-brown colour. 
 
 Dyewoods do not contain in their fresh condition 
 the finished dye colours, but a chromogen capable 
 of being converted into them by oxidisation, or by 
 other influence notably this is the case with log- 
 wood. 
 
 Many chemicals have been tried to hasten the 
 process, but they are not successful, as they tend to 
 redden the wood too quickly, and afterwards to 
 blacken it. Glue is sometimes used to open the 
 pores of the wood by combination with the tannin 
 in the wood, but it is not certain that logwood con- 
 tains any tannin. Curing adds, of course, largely 
 to the bulk of the dye; few dyewoods contain as 
 much as 10 per cent, of colour, and when chips are 
 intended to produce extract, they usually go direct 
 to the extractor, as oxidisation is sometimes con- 
 sidered objectionable. Extractors vary in form in 
 different countries ; they are often open vats with 
 free steam injection, but in Germany and France 
 small, closed circular " Boura " extractors are used. 
 
FOR MANUFACTURING CHEMISTS 63 
 
 They are mounted on trunnions in columns, to 
 tilt, and are fitted with a perforated false bottom, 
 free steam injection coil, and a discharge cock at 
 bottom, and a manhole at top to discharge the 
 exhausted chips when tilted over end ; they are 
 usually worked at 30 Ibs. pressure per square 
 inch. 
 
 In America a large closed type is used arranged 
 as a battery for continuous working, and a pressure 
 of not more than 15 to 20 Ibs. per square inch is used 
 in them. An increase of pressure produces a larger 
 yield, but a decrease of colouring value. 
 
 The liquor is concentrated in vacuum pans to the 
 required density, 42-50 Twaddle = 1210-1255 spe- 
 cific gravity = 12 to 12^ Ibs. per gallon, the vacuum 
 pans used being very similar to those used for con- 
 centrating extract of malt. 
 
 SUPERHEATED STEAM. 
 
 The use of superheated steam is very little under- 
 stood generally, and rarely applied in manufacturing 
 chemistry ; but by its use immense advantages can 
 be gained at very small cost. It enables absolutely 
 dry steam at a constant pressure to be supplied for 
 heating purposes at any desired temperature from 
 215 to 600 F., without any increase of pressure ; 
 i.e., steam can be passed from a steam boiler at say 
 10 Ibs. pressure per square inch at its normal tem- 
 perature of 239 F., through a superheating coil to 
 a, close vessel, becoming raised to say 300 F. (the 
 equivalent heat of saturated steam at 52 Ibs. pres- 
 sure per square inch), while its pressure remains 
 
64 MACHINERY AND APPARATUS 
 
 constant at 10 Ibs. per square inch. Of course the 
 tube surface of any superheater must be equivalent 
 to the desired increase in temperature of the steam. 
 
 The great advantages to be derived from its use 
 are, that as no condensation of the steam can take 
 place, there is no obstruction by condensed water in 
 the pipes, and the steam is therefore delivered dry, 
 and heats the surface evenly to which it is exposed ; 
 and also that great heat can be applied economically, 
 for the evaporation of liquids or drying of powders, 
 etc., with steam at small pressure in vessels which 
 are not constructed of sufficiently strong forms to 
 withstand the necessary pressure equivalent to the 
 same temperature if saturated steam was used 
 instead of superheated steam. 
 
 Steam should never be heated higher than 
 necessary, as very extreme temperatures are de- 
 cidedly destructive to the packing of joints and all 
 forms of lubricating material, 
 
 In the case of a boiler supplying steam to a steam 
 engine, at such a distance that so much condensa- 
 tion takes place in the main as to decrease the 
 pressure, if a superheating coil is placed in the 
 brickwork flue of the boiler of correct proportions, 
 the steam after being passed through it will enter 
 the cylinder of the engine perfectly dry, at the 
 same pressure and temperature as it leaves the 
 boiler, without risk of objectionable overheating and 
 with a distinct saving in fuel. 
 
 A very simple superheater may be formed by 
 surrounding a vertical helical coil of hydraulic 
 wrought-iron piping with brickwork, having its inlet 
 and outlet pipes standing up above the brickwork, 
 fuel, such as coke, being fed in from the top inside 
 
FOR MANUFACTURING CHEMISTS 
 
 65 
 
 and round the coil, the brickwork being open at the 
 top and only covered with a moveable iron plate, 
 and the ashes being raked out from a door at the 
 bottom. In more elaborate forms the pipe is cased 
 in cast-iron blocks, in sections connected together 
 by external pipes, the blocks being set in suitable 
 brickwork settings with properly constructed iron 
 furnaces. 
 
 MALT EXTRACT PLANT. 
 
 The plant necessary for making extract of malt is 
 practically the same as a brewing plant up to the 
 concentration process, when a vacuum pan must be 
 substituted for a brewing copper. The malt being 
 landed in the factory, should be shot into a malt 
 'hopper containing the quantity to be ground for the 
 day's work. This hopper can be of iron or of wood 
 
 E 
 
66 MACHINERY AND APPARATUS 
 
 lined with zinc, the bottom of which should slope 
 not less than 12 ins. in a vertical height of 7J ins., 
 and have an outlet shoot feeding a revolving malt 
 screen, which separates the stones and lumps and 
 drops them into a bin below, also the dust, which is 
 dropped into another bin, while the clean malt is 
 carried through the screen into the mill. The mill 
 should have two horizontal rolls, which can be 
 adjusted to grind coarsely or finely, with a feed-roll 
 above and a magnetic screen to arrest any nails or 
 metal there may be in the malt. It should be 
 fitted in a wooden casing, with convenient doors 
 for examining the rolls and a removable sample 
 tray. 
 
 The mill should either command the grist hopper 
 or be connected to it by an elevator, or Jacob's 
 ladder. The grist hopper can be of similar con- 
 struction to the malt hopper, but should be covered 
 and dust-tight, with large hinged doors in cover. 
 The grist hopper should command the mash tun, 
 and should be connected by a shoot with slides to 
 an outside mashing machine. There are several 
 forms of outside mashing machines for small quan- 
 tities. That known as the Maitland type is the 
 most suitable, and for large quantities a Steel's 
 masher should be used. Their object is to 
 perfectly mix the liquor and the grist together, so 
 that they fall into the tun thoroughly incorporated. 
 The mash tun, which is the most important item in 
 the plant, can be made of cast iron, copper, or wood, 
 preferably of English oak, with fir bottom, and 
 should have a capacity of 108 gallons, or perhaps 
 144 gallons, per quarter of 336 Ibs. of malt mashed, 
 and should not be more than 4 ft. deep. It should 
 
FOR MANUFACTURING CHEMISTS 67 
 
 be fitted with the very best quality of sawn slotted 
 false bottom plates, accurately fitted and having 
 slots about -fa wide by 3 in. long. 
 
 Large mash tuns should be fitted with internal 
 rake mashing machines driven by power. The 
 bottom of the tun should be fitted with an underlet 
 copper main for mashing, a waste cock, and a series 
 of special pipes and taps for running off the clear wort. 
 The number of these pipes varies with the sizes of 
 the tuns, but there should never be less than three. 
 The mash tun should also be fitted with a revolving 
 sparger of any suitable form for sparging the mash 
 after the first wort is run off. A hot liquor tank of 
 ample capacit}' for mashing and sparging should 
 command the mash tun, fitted with a powerful steam 
 boiling coil capable of heating its contents to boiling 
 point in an hour. Beneath the mash tun should be 
 fixed the underback, of about the same capacity as 
 the mash tun, fitted with a copper steam coil to keep 
 the first worts warm while the second are running 
 in, or until they can be drawn into the vacuum pan, 
 to prevent souring. 
 
 The object of the operator is to obtain all the 
 diastase and albuminoids only from the malt, and 
 his mash only differs from a brewer's inasmuch as 
 the brewer's object is to obtain all he possibly can 
 from the malt, i.e. to convert all the starch into 
 maltose and dextrin by the soluble action of diastase, 
 and this depends entirely on the heats used and the 
 length of time of the infusion. The wort can then 
 be pumped or drawn up by vacuum into the vacuum 
 pan, which should be of sufficient capacity to take 
 the whole of the first and second worts at one 
 charge, and the charge should be concentrated right 
 
68 MACHINERY AND APPARATUS 
 
 off to the desired consistency the same day, in 
 about four hours time. 
 
 The vacuum pan should be copper, preferably of 
 a globular form, fitted with steam jacket and two or 
 more copper steam boiling worms, all tinned inside, 
 of large area through the neck and arm pipe, and 
 be fitted with an efficient condenser, preferably of 
 the Torricellian type, connected to a vacuum pump 
 of sufficient capacity to keep a steady vacuum in 
 the pan of 29 in., so that the temperature of the 
 extract in the pan shall never exceed 130 F. 
 
 The extract, when sufficiently concentrated, can 
 be discharged through a measuring filter into a 
 vessel fitted with bottling valves. One quarter of 
 malt, wetted and sparged with 216 gallons of water, 
 should produce about 2 cwt. of extract of malt, and 
 only the finest quality of pale malt should be used. 
 
 STEEL'S MASHING MACHINE. 
 
 The mashing machine, u Steel's Patent," was 
 invented by a Mr. Steel, a brewer, and consists of 
 a cylinder having an internal revolving brake 
 driven by power. One end of the cylinder is con- 
 nected to the mouth of the grist hopper, and is 
 fitted with slides for the regulation of the grist, and 
 directly opposite to the falling point of the grist is 
 fixed a liquor cock. The most modern machines 
 have two or three blades of a screw attached to 
 the feeding end of the rake shaft to start the grist, 
 moving forwards towards the mouth. The mouth 
 of the machine is half covered to keep in the heat, 
 and should have a thermometer attached to it. 
 
FOR MANUFACTURING CHEMISTS 69 
 
 Grist and hot liquor are put into the machine 
 simultaneously, and become thoroughly incorporated 
 by the revolving rakes, rendering mashing a simple 
 and easily managed operation, under perfect con- 
 trol as to temperature desired. This machine gives 
 excellent results, as its mash never sets, being light 
 and buoyant, producing a high extract without loss 
 by dusting ; it occupies very little space, is easily 
 fixed, and requires very little power to drive it. 
 The mashing operation by the use of this machine 
 occupies only twenty minutes with perfect blending, 
 on account of the speed at which the rake shaft is 
 driven. 
 
 To mash 1-3 quarters, the machine should be 8 in. diam. 
 
 4-7 
 
 8-15 
 
 16-30 
 
 30-50 
 
 50-100 
 
 
 
 5? - LV ?) 
 
 10 
 
 " ?j 
 
 12* 
 
 > 
 
 15 
 
 100-200 22 
 
 The machines vary in length from 3 to 8 ft., and 
 can be used to serve two mash tuns by means of a 
 swivelling mouthpiece. 
 
 CITRATE PANS. 
 
 Citrate pans, or steam drying tables, can be made 
 of tinned copper, pewter, or cast iron. Copper or 
 pewter are preferable to cast-iron, as iron is liable 
 to rust when left out of use for any time ; but if 
 constantly in use iron is perhaps preferable, as 
 the surface becomes oxidised, and it retains its 
 
70 MACHINERY AND APPARATUS 
 
 heat without variation of temperature better than 
 metals of higher conductivity, on account of its 
 thickness. They are usually about 5 ft. long, 3 ft. 
 wide x 6 in. deep, jacketed at the bottom with a 
 steam jacket 3 in. deep. Steam enters at one end, 
 and is allowed to escape at the other without pres- 
 sure accumulating. They should be fitted with 
 safety valves in case of accident, and a suitable 
 drain cock and pipe, and be mounted on a light 
 stand to a height of 3 ft., to the top of lip of the 
 table. About 1 cwt. per day can be made in each. 
 Pewter tables vary in substance from f in. to f in. 
 thick according to their size, and should be stayed 
 with copper screw-collared stays and bolts burnt 
 on to the underside of the pewter passing through 
 the cast iron steam jacket, and fastened with nuts 
 on washers underneath. The stays should be spaced 
 about 12 in. pitch, centre to centre, to prevent 
 sagging. 
 
 Copper tables can be made of slight substance, 
 say 4 Ibs. per foot super, and do not require staying, 
 and are therefore cheaper and more generally used. 
 They should be formed of a single sheet of copper, 
 with sides raised up and having their corners 
 brazed, leaving them smooth and flush inside, and 
 having their top edge stiffened by a split brass 
 tube, mitred at the corners and sweated on with 
 pure metal. 
 
 EMULSIFIERS. 
 
 Emulsifiers vary in design somewhat for every 
 kind of emulsion, and no fixed rules can be made as 
 
FOR MANUFACTURING CHEMISTS 71 
 
 to their proportions, as the ingredients often differ 
 so much in consistency and gravity. 
 
 The most common form is the whisking machine, 
 consisting of a closed vessel with removable cover, 
 having a semicircular bottom, with hot water jacket 
 below. It is fitted internally with a hollow horizontal 
 shaft, through which works another shaft, both 
 being revolved in opposite directions by hand 
 gearing carried in framing attached to the outside 
 of the vessel. To each of these shafts are attached 
 discs carrying semicircular-shaped loops of wire, 
 which when revolving cross-cut the mixture, and 
 have a lifting action, causing a voluminous flow of 
 the ingredients. In another form, the same double 
 shaft arrangement is placed vertically and rotated 
 by bevel wheels, straight wire with bent ends being 
 used instead of loops, and being so arranged, that 
 in their revolutions they pass each other closely in 
 opposite directions, so that no portion of the goods 
 can possibly avoid coming in contact with the 
 stirrers. 
 
 Some of these machines are arranged so that the 
 emulsion can be tilted out when finished, and others 
 so that the mixing gear can be raised out of the 
 vessel, and the vessel removed from the machine for 
 emptying. 
 
 Malt extract and oil are rBadily mixed in a vessel 
 fitted with a quick-revolving vertical shaft having 
 a four-bladed propeller attached, which beats the oil 
 down quickly to the bottom, causing it to rise again 
 through the extract, the extract bsing previously 
 diluted with water to reduce its gravity, and water 
 being placed on the top of the oil to prevent air 
 getting beaten into the emulsion. The vessel should 
 
72 MACHINERY AND APPARATUS 
 
 be jacketed or fitted with steam heating pipes to 
 raise the temperature when found necessary, and 
 should also be fitted with a run-off main and 
 bottling valves, from which bottling can take place 
 during the mixing operations. 
 
 PERCOLATORS. 
 
 Percolators are usually made of copper, from 1 
 gallon to 20 gallons capacity, tinned inside and 
 fitted with covers and water seal joints. These joints 
 should not be less than 3^ in. deep, to ensure an 
 absolutely hermetical seal. They can be jacketed 
 for steam or circulation of hot water, and mounted 
 on trunnions if desired, but are generally supported 
 in a stand or on a tripod frame, which can be 
 arranged so that the legs are formed of telescopic 
 tubes to enable it to be raised or lowered to any 
 desired height. Percolators should be preferably in 
 the form of a cone set at an angle of 30, and have 
 a discharge cock at bottom of perfect roundway bore 
 with solid plug. 
 
 PERFUME EXTRACTORS. 
 
 The extraction of perfume from pomade is usually 
 performed by what is known as the cold process in 
 a form of mixing machine. It consists of a close 
 receiver, fitted with a mechanical agitator, and 
 having a large capscrew on its breast. The cap 
 being removed from the screw, the spirit is placed 
 in the receiver, and a vermicelli press is fitted on 
 
FOR, MANUFACTURING CHEMISTS 73 
 
74 MACHINERY AND APPARATUS 
 
 to the screw, through which the pomade is shredded 
 into the spirit. The press is then removed, and the 
 cap fixed on again, and agitation is then resorted 
 to continuously by power, or at intervals during 
 the day by hand, until the spirit has absorbed the 
 perfume in the pomade, when it is run off by a dis- 
 charge cock at the bottom, and frozen to free it 
 from the fat remaining in it. The cover of the 
 receiver is then removed, and the fat scraped out 
 and put in a still to recover the remaining spirit. 
 This is a laborious and tedious process, lasting ten 
 to fourteen days, resulting in serious loss of spirit. 
 A great improvement has been made in this manu- 
 facture through the introduction by the author of 
 a perfected apparatus known as a " Combined Ex- 
 tractor and Still," for extracting perfume from 
 pomade and for recovering spirit, which performs 
 the complete operation of two extractions and re- 
 covery in one day by what may be termed a warm 
 process, as against at least ten days by the old or 
 cold process. The pomade is put into the still to the 
 level of the heating surface, spirit is then added, 
 and the whole stirred to a perfect admixture. The 
 jacket, having been filled with water, is heated by 
 steam until the temperature of the mixture is equal 
 to, but does not exceed, that of the water in the 
 jacket, thus preventing decomposition of the fat. 
 The valve between still and condenser being closed, 
 and the contents properly mixed, steam is turned 
 off, and the still allowed to cool by passing water 
 through the jacket until the pomade sets ; the spirit 
 is then drawn off through the cock in the still body, 
 and the still tilted if necessary. More spirit is then 
 added, and the operation repeated. The valve be- 
 
FOR MANUFACTURING CHEMISTS 75 
 
 tween still and condenser is then opened, the water 
 blown out of the jacket, and the remaining spirit 
 is recovered by steam distillation at a high strength 
 and used over again. 
 
 This apparatus consists of a strong copper still, 
 tinned inside, fitted in a cast-iron jacket for use as 
 a steam or water jacket, supported in trunnions on 
 suitable frames with tilting gear. 
 
 It is fitted with a large capscrew, thermometer, 
 spirit cock and funnel, steam valve, water supply 
 cock, water escape valve, air cock, and discharge 
 valve. The still is surmounted by a flanged copper 
 swan-neck still-head, and lower end connected by a 
 handled union to a valve attached to a tinned copper 
 worm with vapour globe fitted in a galvanized iron 
 worm tank, with copper overflow pipe, plug, washer, 
 and waste and water inlet funnel and pipe. The 
 still is fitted with a cross blade rouser on spindle 
 supported on and working in a stuffing box on swan- 
 neck and stay bar in dome of still, with discon- 
 necting coupling and driving wheel for hand or 
 power driving. The principal perfumes that can 
 be extracted from pomades are cassia, jasmine, lily 
 of the valley, orange, rose, stephanotis, tuberose, 
 and violet. Tinctures such as ambergris, civet, 
 musk, orris, Tonquin beans, and vanilla, etc., can be 
 also rapidly made in this apparatus. 
 
 LIME AND LEMON JUICE CONCENTRATORS. 
 
 Both lime juice and lemon juice are now usually 
 imported in the concentrated form and sold for 
 citric acid manufacture on the basis of 64 oz. of 
 
76 MACHINERY AND APPARATUS 
 
FOR MANUFACTURING CHEMISTS 77 
 
 citric acid per gallon, sp. gr. 1/256. Lime juice was 
 formerly concentrated in copper Teaches over a fire, 
 but this is a very wasteful process, as there is a great 
 loss by carbonization, and the juice becomes loaded 
 with copper and of a very dark colour. Now both 
 juices are usually concentrated by steam in oak vats, 
 fitted with steam coils of pure block tin and with 
 ebonite draw-off cocks. They are best arranged in 
 tiers of comparatively shallow form commanding 
 each other, so that the juice can be passed on from 
 one to the other after a limited time for evaporation, 
 and the product finished in the last one. Raw juice of 
 T035 sp. gr. concentrated to 1*256 sp. gr., reduces 
 the bulk about as 9 to 1 ; and this is as high as it is 
 wise to carry the concentration. 
 
 The boiling vats vary in size from 100 to 400 
 gallons capacity, and are usually arranged in 
 batteries of four. It is advisable to fit them with 
 screw clipped hoops, so that the hoops can be 
 tightened on them without driving them. 
 
 The steam coils should have about 1 ft. of heating 
 surface to every 10 gallons capacity in the vat for 
 rapid concentration, and should be made of thick 
 pure tin pipe and lie flat on the bottom of the vats. 
 
 LIME OIL EXTRACTION. 
 
 For extracting the essential oil from the rind of 
 lime fruit, oranges, and lemons, a peculiar form of 
 appliance is used, known as the " Ecuelle " pan. 
 It consists of a copper bowl varying in diameter 
 from 12 to 9 ins. and in depth from 3 to 1J in., 
 studded all over inside with sharp pointed pins, and 
 
78 MACHINERY AND APPARATUS 
 
 having a hollow handle like a bouquet-holder. The 
 pitch of the pegs varies from f to f inches, according 
 to the size of the fruit. The fruit is rolled round by 
 hand on the points of the pegs, which puncture the 
 skin, and cause the oil to exude and run down the 
 pegs into the bowl and thence into the hollow handle, 
 which when full is poured out into a measure. 
 Another method is to remove the peel with a knife 
 and collect the oil from it with a sponge or to press 
 it out from the peel in a hydraulic press, but pressed 
 oil contains so many impurities that its value com- 
 pares very unfavourably with that collected by the 
 Ecuelle pan, or by the sponge. It can also be 
 separated from the juice by distillation, but the 
 process is not a profitable one. 
 
 HYDRAULIC PRESSES. 
 
 Hydraulic presses for tincture should be 
 thoroughly self-contained and as compact as possible, 
 having their pump or pumps attached to work up 
 to 2^ tons pressure per square inch of the area of 
 the rams and occupying as small a ground space as 
 possible. It is most convenient in small presses to 
 have the press box mounted on wheels arranged to 
 run out on rails for emptying and recharging, but 
 in large sizes, where there is plenty of room between 
 the standard tension bars, it is perhaps better for the 
 mullet to be arranged to run out clear of the box. 
 Great economy can be exercised in the manufacture 
 of these presses by keeping the rise of the ram as 
 short as possible and dispensing with packing pieces 
 of wood in the press box. The press box should be 
 
FOR MANUFACTURING CHEMISTS 79 
 
 ribbed down its sides and ends and fitted with, a 
 perforated lining consisting of bottom and two sides 
 linked together to lift out, together with its loose 
 plates and charge, whether contained in press bags 
 or not. 
 
 A tank can be cast round the cylinder, to which 
 the suction and delivery pipes to the pumps can be 
 
 BENNETT SONS i SHEARS L f . B 
 
 KINCSLAND ROAD, 
 
 LONDON. 
 
 connected, so that the same water is used over and 
 over again. Great care should be taken in the 
 manufacture of these presses, as the slightest fault 
 or flaw in them is often incurable, and renders them 
 practically useless. 
 
 A 20- ton press should have a ram 3| in. diameter 
 x 6 in. rise, with box 2 i- gallons content. 
 
80 MACHINERY AND APPARATUS 
 
 A 30-ton press should have a ram 4 in. diameter 
 x 6 in. rise, with box 8 gallons content. 
 
 A 50-ton press should have a ram 6 in. diameter 
 x 12 in. rise, with box 16 gallons content. 
 
 ALMOND OIL PRESSES, 
 
 Hydraulic presses of special form are used for 
 pressing the oil from almonds. They are usually of 
 the vertical type, having 12 to 60 small plates of 
 square or oblong form, between which the almonds 
 are put in serge and cocoanut fibre matting cloth 
 bags, having been previously crushed into a coarse 
 meal. Standard guide bars are placed against the 
 ends of these plates to keep them straight, these 
 bars being connected to the follower and passing 
 through slots in the press head. "When the follower 
 is raised by pressure, pumps are used for these 
 presses to work them up to 2| tons pressure per 
 square inch, and the oil on running out is caught in 
 a channel cast round the top of the follower, with a 
 spout from whence it runs into a press can, Presses 
 with rams of 5 to 15 in. diameter, exerting total 
 pressures of 50 to 400 tons, are generally used. 
 The pressure is allowed to remain on each charge 
 for some time until the oil ceases running, the pro- 
 duct in oil being generally about 40 per cent, of the 
 weight of the uncrushed almonds. The press plates 
 should be kept as small as possible in proportion to 
 the size of the ram, as it is essential that the 
 pressure should only be distributed over a small 
 surface, as a very great pressure is necessary for the 
 work. 
 
FOR MANUFACTURING CHEMISTS 81 
 
 PUMPS. 
 
 It is always desirable to select a pump of sufficient 
 capacity to deliver the required quantity of water at 
 a moderate piston speed, say 60 ft. per minute. 
 With larger pumps this speed can be increased to 
 75 ft. per minute, or even more. Vacuum pumps, 
 both wet and dry, should be run from 90 to 100 ft. 
 per minute. With thick or hot liquors the speed 
 should be considerably reduced, according to the 
 nature of the fluid to be dealt with and the pressure 
 or head under which the pump is working. By 
 choosing a pump of ample size, it is possible in case 
 of emergency, or when a greater supply is needed, 
 temporarily to. considerably increase the piston 
 speed, thus proportionally increasing the delivery. 
 
 Pumps are always improved by having air vessels 
 fitted both on suction and delivery pipes to obviate 
 air cushioning, and to more or less effectively regu- 
 late and equalize the velocity of discharge. 
 
 One foot head of water equals '43 Ibs. pressure 
 per square inch: thus, 20 ft. = 8'6 Ibs. pressure per 
 square inch. The three-throw pump gives a more 
 uniform discharge than any other form. 
 
 In calculating the sizes of pipes to pumps, it 
 should be remembered that the action of a pump is 
 intermittent, especially where there is no air vessel 
 to regulate the velocity of supply and discharge. It 
 is therefore advisable to have the pipes equal to 
 about three times the area of the mean discharge. 
 
82 
 
 MACHINERY AND APPARATUS 
 
 PIPES. 
 
 The joints of cast-iron water pipes are usually 
 made by sockets and spigots, run in with melted 
 lead, as they admit of considerable departure from 
 the strict straight line which is sometimes very 
 convenient. 
 
 Flanged cast-iron pipes are not very often used 
 for water, but are especially convenient where the 
 joints have often to be broken. 
 
 They should always be used for steam, and should 
 be faced right across the joints of flange. India- 
 rubber insertion is the best jointing material for 
 water, and asbestos or red lead and copper gauze 
 for steam joints. 
 
 CUBIC CAPACITY. 
 
 1 imperial gallon .... 
 
 1 ,, ,, .... 
 
 1 cubic foot of sea water . 
 1 ,, inch of sea water . 
 1 foot of water 
 1 ,, inch of water 
 A cylindrical foot of water 
 inch 
 
 A column of water 12 in. long 1 in. 
 square ...... 
 
 A column of water 12 in. long 1 in. 
 diameter ...... 
 
 The capacity of a 12 in. cube . 
 ,. 1 in. square 1 foot 
 
 long . 
 
 ,, cylinder in gallons 
 
 1 yard long 
 
 = 277-274 cub. in. 
 =016045 cub. ft. 
 = 64-000 Ibs. 
 = 6-057037 Ibs. 
 =62-32 Ibs. 
 =0-036161 Ib. 
 = 48-96 Ibs. 
 =0-0284 Ibs. 
 
 =0-4341 Ib. 
 
 =0-3401 Ib. 
 =6-232 gals. 
 
 =0-0434 gals. 
 
 =0*1 diameter squared. 
 
FOR MANUFACTURING CHEMISTS 
 
 83 
 
 The capacity of 1 in. diameter 1 foot 
 
 long. . . . =0-034 gal. 
 ,, of a cylindrical inch . =0*002832 gal. 
 cubic inch . . =0*003606 gal. 
 ,. sphere 12 in. dia- 
 meter . . =3-263 gals. 
 ,, ,, sphere 1 in. dia- 
 meter . . =0-00188 gal. 
 
 . =277-274 cub. in. 
 
 . =4*543 litres of water. 
 
 . =0-22 imp. gals. 
 
 1 imperial gallon 
 1 
 
 1 litre of water 
 
 = 61 cub. in. 
 =0-0353 cub. ft. 
 
 MEASURES. 
 
 Litres. 
 
 Imperial gallons. 
 
 Pints. 
 
 1 
 
 22 
 
 If 
 
 2 
 
 44 
 
 Si 
 
 5 
 
 ri 
 
 
 10 
 
 2-2 
 
 
 
 20 
 
 4-4 
 
 
 
 50 
 
 11 
 
 
 
 100 
 
 22 
 
 
 
 500 
 
 110 
 
 
 
 1000 
 
 220 
 
 
 
 5000 
 
 1100 
 
 
 
 A litre is *22 of a gallon, i.e. 1 gallon = 4'54 litres. 
 A gallon of water at 62 F. weighs 10 Ibs., and 
 contains 277'274 cubic inches or '16046 cubic feet ; 
 hence a cubic foot of water weighs 62'321 Ibs., and 
 contains 6'2391 gallons or nearly 6J gallons. 
 
 The specific gravity of tallow is '954. 
 
 9 J Ibs. = a gallon. 
 59 Ibs. = a cubic foot. 
 1 stone = 8 Ibs. 
 
84 MACHINERY AND APPARATUS 
 
 THERMOMETERS. 
 
 To translate into Fahrenheit degrees the indica- 
 tions of a centigrade thermometer, it will suffice to 
 multiply the number of centigrade degrees by 1*8, 
 and add 32 to the product. 
 
 Example : 25 C = (25 x 1*8) + 32 = 77 F. 
 
 Inverse calculation is necessary to translate 
 Fahrenheit into centigrade degrees. 
 
 Thus : 176 F. = -" = 80 C. 
 
 i.e. to convert the degrees of one scale into those 
 of the other, a proportion must be made on the 
 basis of the number of degrees separating the 
 freezing and boiling points on the two scales, with 
 the subtraction or addition, as the case may be, of 
 the 32 advantage which the Fahrenheit scale has 
 over the centigrade. This number is as 180 -5- 100 
 or as 9 : 5. 
 
 A 60 Fahrenheit (6Q ~ ^ 2) x 5 = 15'5 C. ; 
 y 
 
 and by inverse calculations to convert 60 C. : 
 6Q , x9 + 32 = 140 Fahrenheit. 
 
 To convert Reaumur scale into Fahrenheit mul- 
 tiply by 9 and divide by 4 and add 32. 
 
FOB MANUFACTURING CHEMISTS 
 TEMPERATURES. 
 
 85 
 
 Reaumur. 
 
 Fahrenheit. 
 
 Celsius. 
 
 Reau. 
 
 Fahr. 
 
 Gel. 
 
 Reau. 1 Fahr. 
 
 Cel. Beau. 
 
 Fahr. 
 
 Cel. 
 
 Reau. 
 
 Fahr. 
 
 Cel. 
 
 -16 
 
 -4 
 
 -20 
 
 16 
 
 68 
 
 20 
 
 48 
 
 140 
 
 60 
 
 80 
 
 212 
 
 100 
 
 -15-2 
 
 -2-2 
 
 19 
 
 16-8 
 
 69-8 
 
 21 
 
 48-8 
 
 141-8 
 
 61 
 
 80-8 
 
 213-8 
 
 101 
 
 -14-4 
 
 -0-4 
 
 -18 
 
 17-6 
 
 71-6 
 
 22 
 
 49-6 
 
 143-6 
 
 62 
 
 81-6 
 
 215-6 
 
 102 
 
 -13-6 
 
 1-4 
 
 -17 
 
 18-4 
 
 73-4 
 
 23 
 
 50-4 
 
 145-4 
 
 63 
 
 82-4 
 
 217-4 
 
 103 
 
 -12-8 
 
 3-2 
 
 16 
 
 19-2 
 
 75-2 
 
 24 
 
 51-2 
 
 147-2 
 
 $4 
 
 83-2 
 
 219-2 
 
 104 
 
 -12 
 
 5-0 
 
 -15 
 
 60 
 
 77 
 
 25 
 
 52 
 
 149 
 
 65 
 
 84 
 
 221 
 
 105 
 
 - 1-2 
 
 6-8 
 
 -14 
 
 20-8 78-8 
 
 26 
 
 52-8 
 
 15-J-8 
 
 66- 
 
 84-8 
 
 222-8 
 
 106 
 
 -1O4 
 
 8-6 
 
 -13 
 
 21-6' 80-6 
 
 27 
 
 53-6 
 
 152-6 
 
 67 
 
 85-6 
 
 224-6 
 
 107 
 
 - 9-6 
 
 10-4 
 
 -12 
 
 22-4 82-4 
 
 28 
 
 54-4 
 
 154-4 
 
 68 
 
 86-4 
 
 2264 
 
 10*J 
 
 - 8-8 
 
 12-2 
 
 -11 
 
 23-2 
 
 81-2 
 
 29 
 
 55-2 
 
 15J-2 
 
 69 
 
 87-2 
 
 228-2 
 
 109 
 
 - 8 
 
 14 
 
 -10 
 
 24 
 
 86 
 
 30 
 
 56 
 
 158 
 
 70 
 
 88 
 
 230 
 
 110 
 
 - 7-2 
 
 15-8 
 
 - 9 
 
 24-8 
 
 87-8 
 
 31 
 
 568 
 
 159-8 
 
 71 
 
 83-8 
 
 231-8 ! 111 
 
 - 6-4 17-6 
 
 - 8 .1 25-6 89-6 
 
 32 
 
 57-6 
 
 161-6 
 
 72 
 
 89-6 
 
 233-6 112 
 
 - 5-6 | 19-4 
 
 7 | 26-4 
 
 91-4 
 
 33 
 
 58-4 
 
 163-4 
 
 73 
 
 90-4 
 
 2354 
 
 113 
 
 - 4-8 
 
 21-2 
 
 - 6 
 
 272 
 
 93-2 
 
 34 
 
 59-2 
 
 165-2 
 
 74 
 
 91-2 
 
 237-2 
 
 114 
 
 - 4 
 
 23 
 
 5 
 
 28 
 
 95 
 
 35 
 
 60 
 
 167 
 
 75 
 
 92 
 
 239 
 
 115 
 
 - 3-2 
 
 24-8 
 
 - 4 28-8 
 
 96-8 
 
 36 
 
 60-8 
 
 168-8 
 
 76 
 
 92-8 
 
 2408 
 
 116 
 
 - 2-4 
 
 26-6 
 
 - 3 
 
 29-6 
 
 98-6 
 
 37 
 
 61-6 
 
 170-6 
 
 77 
 
 93*6 
 
 242-6 
 
 117 
 
 - 1-6 23-4 
 
 - 2 
 
 30-4 
 
 100-4 
 
 38 
 
 62-4 
 
 172-4 
 
 78 
 
 94-4 
 
 244-4 
 
 118 
 
 - 08 
 
 3O2 
 
 1 
 
 31-2 
 
 102-2 
 
 39 
 
 63-2 
 
 174-2 
 
 79 
 
 95-2 
 
 2462 
 
 119 
 
 
 
 32 
 
 
 
 32 
 
 104 
 
 40 
 
 64 
 
 176 
 
 80 
 
 96 
 
 248 
 
 120 
 
 O8 
 
 33-8 
 
 1 
 
 32-8 105-8 
 
 41 
 
 64-8 
 
 177-8 
 
 81 
 
 96-8 
 
 249-8 
 
 121 
 
 1-6 35-6 
 
 2 
 
 33-6 107-6 
 
 42 
 
 65-6 
 
 179-6 
 
 82 
 
 97-6 
 
 252-6 122 
 
 2-41 37-4 
 
 3 
 
 34-4 109-4 
 
 43 
 
 66-4 
 
 1814 
 
 83 
 
 98-4 
 
 253-4 123 
 
 3-2 
 
 39-2 
 
 4 
 
 35-2 
 
 111-2 
 
 44 
 
 67-2 
 
 1832 
 
 84 
 
 99-2 
 
 255-2 
 
 124 
 
 4 
 
 41 
 
 5 
 
 36 
 
 113 
 
 45 
 
 68 
 
 185 
 
 85 
 
 100 
 
 257 
 
 125 
 
 4-8 
 
 42-8 
 
 6 36-8 114-8 
 
 46 
 
 68-8 
 
 186-8 
 
 86 
 
 100-8 
 
 258-8 
 
 126 
 
 5-6 
 
 44-6 
 
 7 I 37-6 116-6 
 
 47 
 
 69-6 
 
 183-6 87 
 
 1016 
 
 260-6 
 
 127 
 
 6-4 
 
 46-4 
 
 8 
 
 33-4 118-4 
 
 48 
 
 704 
 
 190-4 88 
 
 102-4 
 
 262-2 
 
 128 
 
 7-2 
 
 48-2 
 
 9 
 
 39-2 120-2 
 
 49 
 
 71-2 
 
 192-2 
 
 89 
 
 103-2 
 
 264-2 
 
 129 
 
 8 
 
 50 
 
 10 
 
 40 ! 122 
 
 50 
 
 72 
 
 194 
 
 90 
 
 104 
 
 263 
 
 130 
 
 8-8 
 
 51-8 
 
 11 
 
 40-8 123-8 
 
 51 
 
 72-8 
 
 195-8 
 
 91 
 
 104-8 
 
 267-8 
 
 131 
 
 9-61 53-6 
 
 12 
 
 41-6 125-6 
 
 52 
 
 73-6 
 
 197-6 
 
 92 
 
 1056 
 
 269-6 132 
 
 10-4 
 
 55-4 
 
 13 
 
 42-4 127-4 
 
 53 
 
 74-4 
 
 199-4 
 
 93 
 
 106-4 
 
 271-4 
 
 133 
 
 11-2 
 
 57-2 
 
 14 
 
 43-2 
 
 129-2 
 
 54 
 
 75-2 
 
 201-2 
 
 94 
 
 107-2 
 
 273-2 
 
 134 
 
 12 
 
 59 
 
 15 
 
 44 
 
 131 
 
 55 
 
 76 
 
 203 
 
 95 
 
 108 
 
 275 
 
 135 
 
 12-8 
 
 60-8 
 
 16 
 
 44-8 132-8 
 
 56 
 
 76-8 
 
 204-8 
 
 96 
 
 108-8 
 
 276-8 
 
 136 
 
 13-6 
 
 626 
 
 17 
 
 45-6 134-6 
 
 57 
 
 77-6 
 
 2J6-6 
 
 97 
 
 109-6 
 
 278-6 
 
 137 
 
 14-4 
 
 64-4 
 
 18 
 
 46-4 136-4 
 
 58 
 
 78-4 
 
 203-4 
 
 QQ 
 
 110-4 
 
 2804 
 
 13 3 
 
 15-2 
 
 66-2 
 
 19 
 
 47-2 138-2 
 
 59 
 
 79-2 
 
 210-2 
 
 oo 
 
 111-2 
 
 282-2 
 
 13J 
 
86 MACHINERY AND APPARATUS 
 
 The expansion of bodies by heat affords the most 
 convenient method of measuring temperatures. 
 Mercury is used for thermometers from to 600, 
 and alcohol for lower temperatures, because it will 
 not freeze ; and air is used for very high tempera- 
 tures, as its expansion is very regular. 
 
 In the Fahrenheit thermometer there are two 
 standards, 32 or temperature melting ice, and 212 
 on the boiling point of water at atmospheric 
 pressure, the difference between the two points, 
 180 7 being equally divided between them, and the 
 same measure is continued up and down the scale. 
 The centigrade scale has the same fixed points, but 
 they are marked and 100, and the distance 
 between them is therefore divided by 100 points. 
 
 PILL MACHINERY. 
 
 For manufacturing pills on a small scale the first 
 machine required is a combined kneading and 
 mixing machine, to mix two to twelve pounds of 
 mass at a time, which can be worked by hand or 
 power. The mass is then passed to a piping press, 
 consisting of a cylinder with perforated plate 
 bottom, fitted with a plunger, having a square- 
 threaded screwed rod, which is actuated by worm- 
 wheel hand-gear. The mass is put into the cylinder, 
 and forced by the plunger through the holes in the 
 bottom plate in the form of rod or piping. The rod 
 or piping then goes to the rotary pill-shaping and 
 cutting machine, which can be worked by hand or 
 treadle. It is placed horizontally between a pair of 
 
FOR MANUFACTURING CHEMISTS 87 
 
 gun-metal, grooved rollers, revolving at different 
 speeds. 
 
 These rolls are grooved for the sized pill re- 
 quired, and by their rotary motion cut off the rod 
 into pieces, and shape the pieces into pills of equal 
 size. The pills are then placed in a pill-rounding 
 and finishing machine, between plates with adjust- 
 able pressure, one plate having a travelling motion, 
 and the other an eccentric motion. 
 
 Pill-coating is best performed in a copper steam- 
 jacketed pan, with an eccentric and oscillating 
 motion of uniform speed and motion without 
 vibration, the powder being sifted on the pills 
 while the pan is rotated. 
 
 When large quantities are made, the sorting and 
 picking is performed in an automatic pill picker, 
 which sorts out and rejects all those of defective 
 -shape, also all those which are larger or smaller 
 than required, from those of perfect size and shape, 
 and deposits them in boxes provided for the three 
 different descriptions. 
 
 CONDENSED MILK. 
 
 Milk to be condensed should be drawn from the 
 cow in the most cleanly manner, and strained into 
 churns through wire-cloth strainers. It is then de- 
 livered to the factory, and weighed in a special tip 
 weighing-machine. As each lot is weighed it is 
 tipped into a receiver, which commands a vertical 
 capillary refrigerator, over which it runs in a thin 
 stream on the outside surface of a series of tinned 
 
88 MACHINERY A^D APPARATUS 
 
 copper tubes or corrugations, and is collected in a 
 trough at the bottom, and from whence it passes off 
 to the scalding pan or heater. Cold water passes 
 upwards- through the inside of the tubes, entering 
 at the bottom and having its outlet at the top, so 
 that the coldest portion of the milk comes in con- 
 tact with the coldest water, and the cooling is 
 gradual. The milk is cooled in these refrigerators 
 to 2 of the temperature of the ingoing water, and 
 as the milk Hows over the tubes, it is thoroughly 
 aerated as well as cooled to about 60 F., and having 
 a specific gravity of about 1*034, so that the two 
 processes are completed together. 
 
 The heater or scalding pan should be of copper, 
 of large diameter, and shallow, with bell-shaped top 
 and straight sides, and steam-jacketed at bottom. 
 Directly the pan is full of milk it is heated to boil- 
 ing-point by steam as quickly as possible, and in 
 some cases stirred mechanically meanwhile. It is 
 then drawn direct into a vacuum pan, and con- 
 centrated to about 1/300 specific gravity. The 
 vacuum pan should be of copper, half as deep again 
 as its diameter, with steam jacket and copper boiling 
 coils, all tinned over inside. Great care should be 
 taken to make the pan quite smooth and flush in- 
 side, so that there be no spaces in which any secre- 
 tion of particles of milk can take place. It should 
 be fitted with efficient steaming and washing out 
 appliances and a large manhole. None of the joints 
 should be made with red lead cement, but they 
 should be all tinned, then bolted together, and 
 burnt in with pure tin, and the crevice between the 
 joints wiped in flush with pure tin. The pan should 
 also be fitted with an efficient tester, consisting of a 
 
FOR MANUFACTURING CHEMISTS 89 
 
 gun-metal egg-shaped measure, made in halves, with 
 a screw in the centre, and fitted with four cocks, all 
 made to disconnect easily for everyday cleaning. 
 Two of the cocks have connecting pipes, one to the 
 top of the pan and the other to the discharge plug 
 above the discharge cock. The third is an air cock, 
 or break vacuum cock, and the fourth is the sample 
 discharge cock. 
 
 There should also be a large copper save-all be- 
 tween the neck of the pan and the condenser, with 
 a gauge and a pipe and cock connected to the pan, 
 so that the contents can be returned when thought 
 desirable. This save-all catches any milk which 
 primes over from the pan as froth, and traps it, 
 preventing it passing through the condenser and 
 being lost. The pan should, of course, have an 
 efficient condenser and vacuum pump. The milk 
 should be drawn into the pan in a thin stream, and 
 conducted to the bottom by an internal pipe, as it 
 froths very rapidly on meeting the change of tem- 
 perature. 
 
 When sugared milk is to be made, the amount of 
 sugar is calculated for the given quantity of milk, 
 and it is then dissolved in a separate vessel by 
 pouring hot milk on it. The hot sugared milk is 
 then drawn into the vacuum pan, and mixed with 
 the milk that is partially condensed. The sugared 
 milk has to be concentrated more than plain milk, 
 as the addition of sugar tends to partially liquefy 
 the mass. Sugar is usually used in the proportion 
 of 1J Ib. to the gallon of milk. The milk when 
 sufficiently condensed is let down into coolers fitted 
 with mechanical stirrers, when it is- cooled to about 
 70 F., then drawn into drawing cans fitted with 
 
90 MACHINERY AND APPARATUS 
 
 discharge valves, from which the tins are filled, and 
 sealed hermetically immediately. Some makers 
 put a drop of glycerine in each tin of sugared milk 
 to prevent the sugar crystallizing and forming 
 grain, as it is apt to do when it separates itself and 
 remains at the bottom of the tin. 
 
 Under the best management and most careful 
 examination losses will inevitably occur from time 
 to time on account of imperfect milk, and it is 
 evident therefore that cleanliness of the most 
 scrupulous and comprehensive character is the 
 first requisite in milk condensing. The milk must 
 not only be sound, produced by healthy cows from 
 sound and healthy food, and under generous and 
 thoughtful treatment, but it must be kept scrupu- 
 lously clean afterwards, and perfectly free from the 
 influences of taints and ferments, and to this must 
 be added careful watchings of the process and at- 
 tention to details. 
 
 SOAP MILLING. 
 
 Toilet soaps are now almost exclusively prepared 
 by what is known as the milling process, which 
 originated in France. It produces toilet soap from 
 the best and pure soap basis, highly perfumed, of 
 uniform quality and superior finish ; but although 
 it enables much more delicate perfumes to become 
 incorporated with the soap, yet it does not produce 
 such a good lathering soap as the old melting and 
 crutchiiig process. 
 
 The crude soap basis is first cut into bars by 
 
FOR MANUFACTURING CHEMISTS 91 
 
 means of a traversing hand frame, with numerous 
 wires set at equal distances. 
 
 The bars are then fed into a rotary cutting 
 machine containing two discs fitted with knives 
 set at an angle, driven by strap-power, and are 
 cut into chips by coming into contact with the 
 knives, and fall into a hopper below. The chips 
 are then placed on zinc perforated trays, and 
 stacked in a hot cupboard, heated by steam-pipes 
 arranged at the bottom of the cupboard. The 
 cupboard being fitted with a strap-driven fan de- 
 livering air underneath the steam-pipes, and be- 
 coming warmed, the air rises through the soap 
 saturated with the moisture in the soap, and is 
 drawn off at the top by an exhausting fan, and 
 ejected. 
 
 An improved drying apparatus consists of a series 
 of endless bands, delivering the chips from one to 
 the other, running on drums at each end, and 
 supported on rollers at intervals, driven by worm 
 and worin-wheel gear off one vertical shaft, the 
 whole being enclosed in a room over the heating 
 pipes, and being fitted with air supply and ex- 
 haust fans. As the chips fall from the cutting 
 machine directly on to the top band, there is great 
 saving of labour in the use of this apparatus, but 
 it is very costly, and has not yet come into use in 
 England. 
 
 "When the chips are dried sufficiently, they are 
 taken to the mill and fed into the hoppers. The 
 crushing mill consists of four granite rollers of 
 large size, varying from 10 to 18 in. in diameter, two 
 of which are set diagonally over the two first set 
 horizontally. They are arranged with self-feeding 
 
92 MACHINERY AND APPARATUS 
 
 gear, and with roll-cleaning and reversible stripping 
 scrapers. 
 
 The soap chips having been passed once through 
 the rolls and emerging in the form of ribbon, 
 are returned to the hopper, and the perfume and 
 colour are then added, and the process of milling is 
 repeated again and again, until the perfume and 
 colour is evenly distributed and incorporated with 
 the soap. This constant milling pressure also gives 
 the glazed appearance which constitutes the perfec- 
 tion of finish. 
 
 These mills should be set perfectly level on wooden 
 beams fixed in solid concrete beds, and be supplied 
 with ample engine power, as the varying consis- 
 tency of the soap necessitates a great variation in 
 the power required some days the power required 
 being twice as great as on others. 
 
 The perfumed soap in ribbon form is then fed 
 into a squeezing machine, or Peletouse, which con- 
 sists of a taper, or in some cases, a parallel steel 
 screw of varying pitch contained in a cylinder, 
 which carries the soap forward, and compresses it 
 through a die of the desired form at the mouth. 
 There is a perforated dividing plate in front of the 
 die, and the passage between this plate and the 
 die is fitted with an attemperating connection. 
 These machines, of French pattern, are usually 
 driven by worm and worm-wheel gear, but spur- 
 wheel gear will be found more suitable, as the speed 
 is too great for the former function. The bars from 
 the squeezing machines run on rollers on to a table, 
 where they are cut off in suitable lengths for stamp- 
 ing. Hand-stamping machines, fitted with top and 
 bottom dies, are mostly used, but those driven by 
 
FOR MANUFACTURING CHEMISTS 93 
 
 power, and managed by a treadle, perform more 
 regular work, and preserve the moulds or dies in 
 better condition. 
 
 The cakes when stamped are again dried, and 
 stored some time before being packed for delivery. 
 
THIS BOOK IS DUE ON THE LAST DATE 
 STAMPED BELOW 
 
 AN INITIAL FINE OF 25 CENT$ 
 
 WILL BE ASSESSED FOR FAILURE TO RETURN 
 THIS BOOK ON THE DATE DUE. THE PENALTY 
 WILL INCREASE TO SO CENTS ON THE FOURTH 
 DAY AND TO SI.OO ON THE SEVENTH DAY 
 OVERDUE. 
 
 ' 
 
 LD 21-50m-8,-32 
 
YB 15492