OHBMI8TRT. 



[APPARATCi 



Rlasac* answer Tory well ; ? r delicate experiment*, h 



. 



_j ^ny 

 gbs* renal answers the purpose. 



Dr. Faraday suggested, many years ago, a Tory in- 



. 1*. 



' 



. . 



mode of toting, boiling, and otherwise dealing 

 with solution*. It U that of luting slips of window-glass, 

 backs of plat**, and sheets of paper, may be 

 thus used. Test-tubes are also of value ; and are, per- 

 h.ij , especially useful to the beginner, as he can use 

 thfiii for <> many pur]>oses. 



We may here suggest a very simple contrivance, which 

 will aid the student in pouring liquids between un- 

 lipl-cd vessels, such as flasks and bottles. If a liquid be 

 |oiirod out of such, it has a tendency to run down the 

 side ; but if a glass rod be placed so as to rest against 

 :o. the odg f the vessel out of 



which the liquid is being 

 poured, and with its other 

 extremity inserted inside tho 

 ^gv* w i receiving-vessel, but not touch- 



1. 1^ / ing it, the liquid may then 



bo passed from one to the 

 other without the loss of a 

 drop. The mode of doing this 

 U illustrated in the annexed 

 engraving. 



In some cases an intense 

 heat is required, as in the 

 fusion of substances containing silica or flinty matter. 

 Fur thin purpose some form of furnace is needful 

 An ordinary lire-place may be used ; coke being em- 

 ployed as a fuel. A most convenient furnace, sug- 

 gested by Dr. Faraday, answers admirably ; and hav- 

 ing constantly employed it, wo recommend its use to 

 our readers. It is made by boring holes, an inch in 

 r, at equal distances, through the outside of 

 a blue pot, such as is used by refiners. The holes are 

 easily made, and should be neatly finished off. An 

 iron grid U dropped in so as to rest two inches above 

 the lower series of holes, and tho fuel may be small 

 pieces of coke or charcoal The furnace should be 

 11. bound round by iron wire, so as to 

 prevent it falling to pieces on being 

 heated. One of these will last for a 

 long time, and is useful for almost 

 every purpose which a chemist can re- 

 quire. Its cost is very slight, being 

 not more than a couple of shillings 

 altogether. The annexed engraving 

 represent* one of these simple 

 tnvances. 



The instrument-makers sell furnaces of every variety of 

 form, suitable for tho piirjxm's to which they may be ap- 

 I n Homo cases, an Argand spirit-lamp may be used ; 

 but if a supply of gas be accessible, a convenient furnaco 

 for nvi-ry |-wies of heating purpose may be readily made 

 M follows: Fix on the end of a cylinder of iron, eight 

 inches long and three inches wide, some wire gauze, so 

 that tho lattor may entirely close one end of tho 

 cylinder. Into th lower part of the cylinder intnluc.i 

 a gas-pipe, having first bored several holes beneath tli.-it 

 viigh which tho pipe passes. These will admit a 

 supply of air, which will mix with tho gas as it issues 

 fi'.m tho gauze. If the gas be ignited, it will burn 

 with a blue flame, affording little light, but an intense 

 beat Tho heat can be regulated with the greatest 

 nicety ; and the most gentle evaporation, or the fusion 

 of siliceous compounds, can bs carried on with the same 

 arrangement Fit;. 23 represents the usual way of 

 carrying out this luef ul modo of heating. 



In in.wt chemical laboratories, the gas furnace is consi- 

 i niply liocauHo the heat produced 



l.y it is so easily regulated, but also on account of its 

 and from not producing dust or sooty matter. 

 A very ingenious arrangement has lately 

 been produced by Mr. Griffin, of Bunhill- 

 ruw, London, which has come largely into 

 use for chemical purposes, and is also em- 

 ployed by uietallurgUts in coses wherein an 

 intense heat is froquently required. The 

 principles of its construction are similar to 

 those of the gas furnaces which we huvo 

 already described; but as it can afford a 

 temperature sufficient to melt cast iron, and to soften 

 almost to the fusing-point, both wrought iron and pla- 

 tina, we shall in- 

 troduce a descrip- 

 tion of its ar- 

 rangement. 



Our illustra- 

 tion (Fig. 23) 

 will give an idea 

 of this arrange- 

 ment when in 

 use. On the right 

 ' is the gas-fur- 

 nace placed on a 

 table ; in tho 

 centre we have 

 the bellows which 

 supply the air- 

 blast, driven by 

 a man, who at 

 the same time can 

 superintend tho 

 entire operation. 



o Is the Iron cylinder ; J, the iheet of wire 

 (rauze ; c, the pipe supplying gas ; d, the ori- 

 fice whence the gas escapes into the cy- 

 linder; f f, are hole* through which air 



enters the cylinder. 



Fig. 24 is that portion through which tho air and gas 

 pass together. Fig. 25 shows the holes at the top of 

 Fig. 23. 



con- 



Fig. 24, which only represents them in section. These, 

 in fact, form tho heating portion of the furnace. 



Mr. Grittin has adopted two different methods of apply- 

 ing heat. In some cases, he prefers to drive tho heat 

 downwards ; in others, the heat is applied from beneath. 

 The following engravings illustrate the plans by which 

 the heat is applied from above. 



Gas Furnace healed at the top, txhiMcd in Section by 

 'Fig. 26. a is tho gas-burner ; 6 is tho support for it, 

 when used 1 elow the furnace; c is the iron tripod sup- 

 port for the furnace; d d are t\\ <> | lynlateB, 

 adapted to tie gas-burner, a; e e are two clay cylinders. 



The interior of the furnace, as represented by Fig. 

 '-'il, in built up as follows: The clay plate, d, is put 

 upon the tripod, c. Over tho central hole in d, the clay 

 eylinder (Fig. 27) is placed, and upon that cylinder two 

 or three of tho clay plates represented by Fig. 28. 

 Upon these a porcelain or platina crucible is placed. 

 If it bo of platina, a piece of platina foil may bo put 

 between the crucible and the uppermost clay plate, to 

 protect tho crucible from contact with particles of iron, 



