232 Mr. Cooper's Lamp Furnace, 



ART. V. Description of Mr. Cooper's Lamp Furnace, for 

 the Analysis of Organic Bodies. 



HAVING had occasion to use Mr. Cooper's lamp for the analysis of 

 organic bodies, described in the last volume of the Transactions of 

 the Society of Arts, and having found it very effectual, we have 

 taken the following account of it from that work, with an abstract 

 of the method of using it; and are enabled by Mr. Cooper's 

 kindness to add the description of some improvements which he 

 has since made on the original apparatus. 



Fig. 1 . Plate i v. a a and b 6, are two long spirit-lamps, each having- 

 ten burners and wicks, the burners of each lamp sloping towards 

 those of the other, as seen in the end view, fig. 2. They are placed 

 in a tin tray c c, mounted on four feet. This tray is perforated in the 

 middle the whole length of the lamp, and as wide as e e, fig. 2. 

 The object in sloping the burners is, that they may clear the lamps 

 and approach each other as near as is requisite, yet leave free space 

 for a current of air, the tray being perforated and mounted on feet 

 for this purpose : d d are spring wires at each end of the tray, 

 to receive the tube ff containing the substance to be analyzed, and 

 to hold it over the flames ; by pressing the shoulders g g, fig. 2, 

 the wires open to receive the tube, and close on removing the pres- 

 sure ; and should the tube be shorter than the lamps, an additional 

 support on a leaden foot, fig. 3, is placed through the openjpg e e 

 of the tray to rise between the flames, and hold the end of the 

 tube. 



The tubes are coated with copper foil, wrapped spirally round 

 them ; if each succeeding fold be on half the other, there will be a 

 double coat of copper all the way, if on two-thirds, there will be 

 three layers of copper, by which the glass tube is prevented from 

 bending when hot, and becomes very uniformly heated. The spi- 

 rals are continued beyond the end of the tube to reach the support, 

 and leave the end within the flames. The dotted line at A, fig. 4, 

 shews the end of the tube short of the support, the foil is secured 

 at the last coil by binding wire, as at i. 



