Apparatus for difengaging Oxygen Gas. 33 



with the hands under water, which is to be changed from time to time. This wafliing is to 

 be continued until the laft quantity of water made ufe of is no longer difcoloured. The fub- 

 ftance remaining in the hands is the glutinous matter of a whitiJh grey colour. If the 

 corn be good, this is elaftic ; (that is to fay, it may be drawn into long firings, -which have a 

 difpofition to flirink or contract. ) If the corn has begun to heat, it is fliort or brittle. If , 

 it has fermented, it will afford none of this glutinous matter. 



X. 



Dcfcription of an Apparatus for difengaging Oxygen Gas, and applying it to the bejl Advantage. 

 ConJlruElcd by J AMES SadlSR, EJq. Chemijl to the Admiralty. — To which are added, 

 Ohjervalions upon the Blonv-Pipe. By W. N. 



Jr I G. I. plate 2, reprefents the vertical feftion of a furnace. The ftiadcd parts denote 

 brick work. A is the afli-hole, B the^rate upon which the fuel is placed, C the opening 

 for the reception of the fuel. It is covered with a piece of fire (tone, or an eartlitn cover, 

 at all times except when a fupply of fuel is wanted. D is the aperture leading to the 

 chimney F; and between D and F is a chamber for the reception of a mattrafs or other 

 veflel ii, to be expofed to the adion of the flame. The veffel E is put in its place, or 

 taken out, by the opening at the upper part of the chamber ; and when at work, that open- 

 ing is clofed by two pieces of fire (lone, each of which covers half the aperture, and meet* 

 the other by a perfe£l ground edge, having a notch that leaves a fpace for the neck of the 

 veflel. Fig. II. is a ground plan of the fame furnace, with the apparatus for receiving and 

 applying the oxygen. The letters B, E, F, denote the fame parts as in fig. i. Fig. III. 

 exhibits a vertical fc£liou of the mattrafs, and other apparatus, denoted by the fame letters 

 as in fig. 2. E is the mattrafs containing black oxyde of manganefe. H is a refrigeratory 

 through which the tube of communication pafles. I is a receiver forcondenfable vapour. 

 The elailic fluid pafles through the tube at K into the receiver L, inverted in another veflel of 

 water M ; the receiver being fufpended by a fl;ring pafllng over a pulley, which therefore 

 admits of a variation at pleafure of the reaclion for extruding the air through the blow- 

 pipe N P. The part N of the blow-pipe is of porcelain ; and a lamp O is placed beneath 

 for the purpofe of heating the air before it iflues from the orifice P. The letters G, K, . 

 and Q5_ denote cocks to be occafionally clofed when the receiving apparatus is required to be 

 feparated or removed. 



The advantages of this apparatus are, firft;, the fimplicity of the furnace, which is appli- 

 cable to a variety of ufes, as well as that particularly flatcd in this account. As the current 

 of atmofpheric air from A, through the grate to B, D, and F, docs not pafs above the root 

 of the paflTage D ; the upper part of the fire-place towards C, where the combuition can- 

 not, reach, may be confidercd as a repofitory for fuel, upon the principle of the athanor, 

 and might, if required, be made equally capacious. 1 his fuel, before it arrives rit the place 

 of combuftion, ferves alfo as a cover when the aftual cover is taken pff to fupply the confump'- 

 tion; befides which, there is not the lead poflibility of deranging or difiurbing tlie veflels on 



fuch occafions, as is too often the cafe in tlie common air furnace. The aperture at t. 



'. -^ . . .^. . < ... . , 



,'-Vot. II.— April 1798. F affbrds 



