LABORATORY. 



many ingredients, but none are equal, or 

 superior, to clay and sand ; viz. sand 3, 

 or 4, or 5, or 6, to clay 1. These are 

 for luting vessels together, and for coat- 

 ings. But in lining furnaces, Dr. Black 

 used a double lining; first, a charcoal- 

 lute ; secondly, a fire-lute. 



He found that a layer of powdered char- 

 coal, beaten up, or kneaded, with as little 

 water as will give its particles adhesion 

 enough to attach itself to the metal sides 

 of the furnace, by means of cautious beat- 

 ing, forms a firm stratum, which is the 

 most imperfect conductor of heat of all 

 that he had tried. When this layer of 

 charcoal is defended from the action of 

 the air by a layer of fire-lute, composed 

 of one part of fine clay, and three or four 

 parts of sand, carefully put on, and con- 

 solidated by gently beating it from day to 

 day, till it no longer receives an impres- 

 sion from the mallet, it will last as long 

 as any part of the furnace. Its durability 

 will be greatly improved, without much 

 change in its conducting power, by using, 

 instead of pure water, water made mud- 

 dy by about one-twentieth of pipe-clay. 

 If finely powdered charcoal be kneaded 

 with one-fifth of pipe-clay, it may be 

 kneaded and formed into any shape, and 

 will be so impervious to heat, that a bit of 

 it may be held in the fingers within an 

 inch of where it is red hot. Such a com- 

 position is, therefore, very proper for the 

 doors of furnaces, and for stopples for such 

 apertures as must be frequently opened 

 and shut. 



Fig. 4, represents an Argand's lamp ca- 



Eable of being adjusted at different 

 eights, by a sliding socket, on a stem or 

 rod. Another similar socket is seen above, 

 into which a ring of wire is inserted for 

 supporting the retort, a, at any required 

 distance above the flame. A third socket 

 may be added, still higher upon the stem, 

 for supporting another wire, which will 

 afford the means of steadying an alembic, 

 or any other apparatus, by a string or 

 small flexible wire answering the same 

 purpose. This is a very convenient 

 method of disposing vessels for the lamp 

 heat, upon a small or moderate scale, for 

 distillations, sublimation, evaporation, 

 drying, and the like. A small sand-bath 

 may be placed, when needful, in the 

 wire above the flame : b is an interme- 

 diate condensing vessel, called a quilled 

 receiver, which conveys the condensed 

 product into a bottle, c. The rod which 

 supports b shows how useful these instru- 

 ments are in their various applications. 



The condensation of vapours after dis- 

 tillation, and the transmission of gases, 



which may arise along with them to their 

 receptacles, has been very well and scien- 

 tifically effected by the late Mr. Woulfe, 

 in an apparatus of bottles which is dis- 

 tinguished by his name. The original 

 contrivance will be easily understood by 

 description, and instead of a drawing of 

 that arrangement of vessels, we shall give 

 one of the most simple, safe, and conve- 

 nient, of all the improvements which have 

 since been made in it ; namely, that con- 

 trived by Dr. Hamilton, and figured at 

 the end of his " Translation of Bertholiet 

 on Dyeing." Suppose the retort and re- 

 ceiver, (fig. 1.) or any other distillatory 

 apparatus, to have a communication from 

 the upper parts of the receiver, a, at c, by 

 a tube leading into a bottle having three 

 necks, and partly filled with water, be- 

 neath the surface of which the said tube, 

 after passing this, an air-tight cork was 

 plunged. Another of the necks of the 

 bottle is provided with an upright open 

 tube, also passing a cork, and plunged in 

 the water, in order that air may enter in 

 case of absorption, or the liquid may rise 

 a little in it, in case of pressure from with- 

 in. The third neck of the bottle affords 

 a communication by means of a tube with 

 another two necked bottle, fitted up in 

 all respects in the same manner as the 

 bottle communicating with e. And in 

 this manner we may conceive a series of 

 three or more bottles, the last of which 

 may communicate with a pneumatic ap- 

 paratus which is to receive the incondens- 

 able gas. This system of bottles and 

 tubes is sometimes fitted together by 

 grinding, and sometimes made secure by 

 lutes; but in most constructions, though 

 the advantages are very considerable, the 

 apparatus is difficult to be put together, 

 and easily deranged or injured. 



Pig. 5, represents Dr. Hamilton's appa- 

 ratus. A is the retort fitted by grinding 

 into a plug or piece, B, represented at 

 b, which last is also fitted by grinding into 

 the neck of a globular receiver, C. 



The use of the additional piece, b t is 

 to afford a due inclination to the retort by 

 an obliquity of its perforation or hole, in- 

 stead of allowing it to remain horizontal, 

 as it would, if fitted to the hole in C, and 

 also to facilitate the grinding in of a new 

 retort, in the case of breakage. The piece, 

 1), has a stopper, a, which can be put 

 whenever the retort is taken out, whether 

 for weighing at, or for any other purpose. 

 The first receiver, C, has a smaller neck 

 opposite to B, which is ground into a cor- 

 responding neck of D, the second receiver, 

 which last is tubulated, and has a tube, 

 H, open at both ends, ground into its ver- 



