CHEMISTRY. 



Chemical are wasted. The rapidity of the flow of water is regu- 

 App-iratus. i ate d by the cocks x, z. The water makes its way into 

 ' the air-holder by the holes ir, n, drilled in the plate to 

 which its bottom is ground, it is a wire to conduct the 

 electricity ; and k is the wire which conducts the elec- 

 tricity from the receiver i. 



12. In many experiments, retorts or flasks furnished 

 with stop- cocks are requisite. They are first exhausted 

 by means of an air pump, and then filled with the gas to 

 be experimented upon. Thus all contact of water may 

 be prevented, and the gases may be previously dried at 

 pleasure. 



13. The various tubes used by chemists under the 

 name of eudiometers, do not seem to require a particular 

 description. 



CHAP. III. 



Apparatus for Experiments on Liquids. 



SEVERAL of the vessels employed in experiments on 

 liquids, as retorts and flasks, have been already men- 

 tioned. We shall take notice of a variety of other 

 vessel?. They are in general so simple, that they will 

 be easily understood without much explanation. Fig. 

 10. represents a balloon glass receiver; and Fig. 1. a 

 matrass, with a wire twisted round its neck to hold it 

 by when hot. Fig. 2. is a fe las? funnel. Fig. 3. a preci- 

 pitating vc^-l. Fig. 4 represents a copper ti!l fit- 

 trd into a furnace, wif'i the worm and refrigetory. n 

 is the still, 6 the head, c the worm passing through tlic 

 refriiretory, which is supposed to be full of water. Fig. 

 5. is a glass alembic for dist llation, fitted with its head 

 and receive--, a, is the alemSii-, ft the head, c the receiver. 

 ITouIfe's Figure 6. represents a Wor.lfe's apparatus fitted up 



aratus. for distillation : a is a stand, t> a lamp, c a retort fixed 

 .6. .,; the lamp by means of the ring on the stand, d the 



receiver standing on the support e, /a tube of safety 

 passing from the receiver to the jar ir : h a tube passing 

 from the jar g to tin jnr '. The'-e jars may be continu 

 ed at pleasure, and the tube from the last jar may pass 

 under a glass vessel standing in a water or mercurial 

 trough, to receive any gas that comes over. Each of 

 the jars contains a quantity of water, into which the tube 

 that enters into it is plunged. In the bend of the tube 

 of safety there is a little water or mercury, to shut out 

 the communication of the external air. The original of 

 this apparatus must be referred to Glauber, who has re- 

 presented it in his work on furnaces. The improvement 

 introduced by Woulfe was to have a considerable quan- 

 tity of water in each jar, by means of which, in many 

 cases, a great deal is saved that would otherwise be lost. 

 All the joinings are to be well luted. The tube of 

 bafety prevents any bad accident from happening in the 

 course of the distillation. If there happen to be an ab- 

 sorption of air within the apparatus, as is often the case, 

 the external air rushes through the tube of safety and 

 fills up the vacuum. These apparatus arc fitted up in 

 a variety of ways by different chemists ; but, after the 

 remarks already made, they may be easily conceived by 

 our readers without any farther description. 



The other vessels employed in experiments on liquids do 

 not seem to require any particular explanation. They 

 will be easily understood by any person who attends to 



159 



expe- Chemical 



Apparatus 



r K Y. 



the properties of the various liquids subjected to 

 riment. 



CIIAP. IV. 



Apparatus for Experiments on Solids. 



THE first and most essential piece of apparatus for ex- Apparatus 

 perimenting on solid bodies, is the furnace. The French for eiperi- 

 havc a great advantage over British chemists in the light, ^ s * U 

 cheap, stoneware furnaces, so easily procured in Paris. 

 They are so light as to be easily manageable, and so 

 cheap as not to be beyond the purchase of the poorest 

 experimenter. It is rather, surprising that they have 

 not been introduced into Great Britain. They might 

 be constructed with the utmost ease by our potters and 

 crucible makers ; and the sale, from the many advanta- 

 ges which they possess, could not but be extensive. 

 When properly hooped with iron on the outside, they 

 would, probably, answer very well for our pit coal 

 fuel. 



The best account of furnaces in any English book Furnace. 

 that we have seen, is in Lewis' P/iilosop/iicat Commerce 

 of the Arts. The practical chemist would do well to 

 consult that excellent treatise. A great variety of fur- 

 naces are employed by chemists ; but the irind furnace 

 may be made to answer almost every purpose. It may 

 be raised to as high a temperature as the blast furnace, 

 by making its chimney of the proper height. We have 

 seen a heat of l6o Wedge wood produced in a very 

 small wind furnace, and iron melted in it \vith great fa- 

 cility. We shall give a short description of the most 

 improved form of Black's portable wind furnace, the p tATK 

 one commonly employed in this country. Figure 7 is CXLIII. 

 an outline of the furnace, and Fig. 8. a section of it. Figs. 7, 8. 

 The same letters indicate the same parts in both figures. 

 It consists of an oval iron cast-, 22 inches high, 20 in its 

 largest diameter, and 15 in its shortest, lined with fire 

 brick or fire clay fcr about three-fourths of its height 

 fn>m the top, which part forms the body of the furnace, , 



while the under part, which is not lined, forms a very 

 spacious ash pit. a a, Is the body of the furnace, 

 which is cylindrical, but a little oblique, that the flame 

 of the fuel may heat the sand more equally than if it 

 were a straight cylinder. The breadth of this cylinder 

 r, S I inches, <tnd its height 15. The grate c lies across 

 the bottom. This fire place has the following opening* 

 above the grate : The highest is the large opening at 

 the top, which, when a sand heat is employed, receive! 

 the sar.d pot /, and, when this is not wanted, is covered 

 by a thick iron plate lined with clay. The next open- 

 ing is the elbow of the chimney f, which widens as soon 

 as it takes a perpendicular direction, and for the first few 

 inches forms a part of the iron case of the furnace, and 

 is lined with clay. After which it is elongated by an 

 iron tube fitted to it, and not represented in the Figures. 

 The degree of heat is regulated by varying the length 

 of this iron tube. The third opening e serves to intro- 

 duce fuel, and may be employed also to regulate the 

 heat. The fourth opening consists of two small round 

 holes gg opposite to each other on the two sides of the 

 furnace. Through them a porcelain or iron tube is oc- 

 casionally introduced, when it u required to be heated to 

 redness for any particular experiment. The last opening 

 d is intended for introducing a muffle. All these open- 



