ORGANIC ANALYSIS. 



701 



FIG. 87. 



trough form (Fig. 87), 22 to 24 

 inches long and 3 inches high. 

 The bottom is 3 inches wide, with 

 narrow apertures about half an 

 inch apart, which form a sort 

 of grate ; the sides of the fur- 

 nace are inclined outwards, and 4i inches apart at top. To 

 support the combustion tube, pieces of strong sheet iron of 

 FIG. 88. tne f rm D, (Fig. 88), are rivetted to the 



(bottom of the furnace, at intervals; they are 

 of exactly equal height, with their edges 

 ground flat, and correspond with the round 

 aperture in the front of the furnace, A. The furnace rests 

 upon two thin bricks supported upon two blocks of wood, which 

 are separated a little by a wedge, so as to elevate slightly the 

 further end of the furnace as in Fig. 89. 



FIG. 89t 



When the heat is to be increased, the furnace is raised a 

 little on one side, by a thin bit of tile placed below. Good 

 charcoal, is the fuel employed in this furnace ; the combustion 

 may be animated by fanning the burning embers with a square 

 piece of pasteboard ; which is safer than raising the furnace 

 off the bricks. Immediately connected with the combustion 

 tube, by means of a perforated cork, is a tube of the form b 

 (Fig. 89), containing fragments of strongly dried, but not fused 

 chloride of calcium. In this tube is condensed the water 

 formed in the combustion, of which the weight is ascertained 

 by weighing the tube, before and after the combustion. Beyond 

 the chloride of calcium tube and connected with it by a short caout- 

 chouc tube, c, is a glass instrument^; m r, containing a strong 

 solution of caustic potash, of density 1.25 to 1.27, for the ab- 



