336 



LABORATORY. 



different sixes, in some places extending down to the 

 floor, for the reception of substances employed in a 

 course of demonstration, and which it is not neces- 

 sary to keep in vials and bottles, such as the common 

 metals and many earthy and metallic salts , besides 

 for the numerous tools, as knives, files, girilets, for- 

 ceps, and other indispensable articles, na corks, 

 valves, or glass plates, stirrers, strings, bladders, tow, 

 matches, sand, tapers, glass, metallic, and earthen 

 tubes, stop-cocks, &c., &c. Two or three portable 

 furnaces, of different sizes and shapes, may have a 

 place near the wall for ordinary furnace operations ; 

 and a recess in the wall, centrally placed, and about 

 four feet from the floor (similar in shape to a common 

 fire-place), should be provided, with a strong draught, 

 for those experiments which are attended with dan- 

 gerous exhalations. The seats may be arranged as 

 is usual in other lecture-rooms. The floor room upon 

 the other side of the partition may be divided, length- 

 vise of the building, into two apartments, separated 

 by a narrow space-way, one of the rooms having 

 double the dimensions of the other ; the larger is the 

 working-room ; the smaller, an apartment for receiv- 

 ing delicate articles of apparatus, as balances, elec- 

 trical machines, air-pump, &c., and which would be 

 liable to injury if exposed to the attacks of the damp 

 and corrosive vapours that are continually floating 

 about in the other rooms. The entry communicates 

 with the theatre by a door ; a double door, also, con- 

 nects the working-room and the lecture-room. The 

 whole floor of the working-room is paved with brick 

 or stone. The first fixture of importance in this 

 room is the general working furnace. Its use is 

 partly domestic, partly chemical ; for it is intended 

 to warm and air the place, occasionally to heat 

 water, as well as to supply the means of raising a 

 crucible to ignition, or of affording a high tem- 

 perature to flasks and evaporating basins, through 

 the agency of a sand-bath. It is built with a table 

 top. The fire-place itself is constructed of brick- 

 work, with iron front and fittings, and the flue, being 

 carried horizontally for three or four feet, is after- 

 wards carried off to, and connected with, the main 

 flue existing in the wall. The fire-place and horizontal 

 flue are covered with a large plate of cast iron, of 

 from two to three feet in width ; this is formed, in 

 the middle, over the heated part, into sand-baths ; a 

 round, moveable one over the fire itself, and a long, 

 fixed one over the flue. The sand-baths supply 

 every gradation of heat, from dull redness, if required, 

 down to a temperature of 100, or lower, whilst on 

 each side of them exists a" level surface, which answers 

 every purpose of an ordinary table, and supplies 

 extraordinary facilities to experiments going on in 

 the sand-bath or furnace. This furnace may be 

 advantageously placed directly against the wall which 

 separates the working-room from the theatre. A 

 large, flaring, wooden hood should be suspended over 

 the sand-bath, to receive the fumes evolved during 

 the digestions and solutions made upon it, and to 

 conduct them away into the chimney. (For a parti- 

 cular description of this furnace, see Faraday, On 

 Chemical Manipulations, p. 90.) Near by may be 

 placed another furnace for heating a large copper 

 boiler, intended to supply the laboratory with hot 

 water ; the boiler should also be fitted with a head, 

 worm, and refrigerator, in order to provide an occa- 

 sional supply of distilled water. The tables should 

 be as extensive as the room will allow, and be so 

 placed as to admit of ready access ; hence a large 

 one, placed towards the middle of the room, and in 

 such a situation as to be well lighted, is very useful. 

 It should be made strong, and furnished with drawers, 

 unless it be closed in with doors, so as to form cup- 

 boards. To protect it from corrosive fluids, as acids 



and alkalies, it should be covered with sheet lcid, 

 In a corner, and as much out of the way as possible, 

 a sink of SLone, or of strong wood-work lined with 

 lead, must be provided. It must be supplied with 

 water, if possible, from a cistern or aqueduct, since 

 an unlimited supply of water is demanded in a labo- 

 ratory. A place in its immediate neighbourhood is 

 to be appropriated to the cleansing accompaniments 

 of a sink, such as pails, pans, sponges, brooms, 

 brushes, &c. Between the table and the working 

 furnace may be placed the pneumatic cistern, which 

 should be of larger dimensions than that employed 

 in the theatre. If the surface of water be 19 inches 

 by 28, and a well be formed at one end of 14 inches 

 by 10, and 12 inches in depth, so as to leave a contw 

 nuation of shelf surface, on three sides of the well, 

 of ^5 inches in width, it will be found sufficiently 

 large for almost any purpose. It should have shel f 

 room sufficient to hold several jars of gas at once. It 

 should be filled with water until it is 1-| inch or l- 

 inch above the shelf, and should be provided witli a 

 stop-cock, by which the water may be drawn off 

 when it has become acidified or dirty. Such a trough 

 is best made of japanned copper, and supported in a 

 wooden frame, so as to stand about 39 inches from 

 the floor; or it may be made of wood, and lined with 

 sheet lead. Unless the establishment is very exten- 

 sive, one mercurial cistern will answer for both rooms; 

 it may be shaped out of marble or soap-stone, or be 

 made of cast iron, and mounted upon a firm frame, 

 fitted with rollers. Cupboards are very useful ; and 

 at least two large ones, with shelves, ought to be 

 provided, in order to preserve chemical preparations, 

 and the neater sort of apparatus, from the dust and 

 dirt which are constantly moving and settling in the 

 laboratory. All parts of the walls within reach 

 should be fitted up with shelves, in a firm manner, to 

 receive bottles and jars ; also a tube-rack should be 

 provided, to hold pieces of glass tube, from one to 

 three feet long. A part of the wall should be fur- 

 nished with long spikes, to hold retort and flask rings, 

 large bent tubes, siphons, coils of wire, iron tongs 

 for holding flasks, &c. Among other indispensable 

 furniture may be enumerated the following articles : 

 one or two large wooden blocks, to serve as bases on 

 which to put heavy mortars ; an anvil, or spike with 

 its foot-block ; a vice affixed to a side table ; ham- 

 mers ; cold chisels ; a screw-driver ; saws ; cutting 

 chisels ; gimlets ; brad-awls ; half-round, flat, and 

 small three-square files ; forceps ; a trowel ; a sold- 

 ering iron, with its appendages ; a glue pot ; nails ; 

 screws ; spatulas of silver, ivory, steel, and wood ; 

 corkscrew; shears; blow-pipes; scratching diamond, 

 &c. A number of filtering stands, supports for retorts 

 and flasks, and wooden forms for holding glass eva- 

 porating basins, flasks and receivers, should be 

 provided ; also a great variety of common, kitchen, 

 open furnaces. The cellar beneath the working- 

 room should contain the more bulky articles, and such 

 as do not receive injury from a slight degree of mois- 

 ture, as lute-sand, charcoal, bricks, carboys of acid, 

 voltaic troughs, &c. We do not go into a description 

 of the common glass apparatus which is essential to a 

 laboratory, as, retorts, adopters, receivers, matrasses, 

 flasks, precipitating glasses, &c., &c., since these 

 articles have come to be well known, under their 

 appropriate names, in every large city where philoso- 

 phical apparatus is manufactured. Doctor Henry 

 recommends that the painting of that part of the 

 laboratory furniture which is exposed to the action 

 of acids, be done with the sulphate of lead. 



Laboratory, in military affairs, signifies that place 

 where all sorts of fireworks are prepared, both for 

 actual service and for experiments, viz. quick matches, 

 fuzes, port-fire, grape-shot, case-shot, carcasses, and 



