Dr. Debus on the Action of Nitric Acid on Glycerine. 205 



paper. Some of the solid compound^ well dried; was placed 

 with some iodide of a;thyle in a sealed glass tube and kept for 

 seventy hours at 110° C. Only a very small portion of the 

 glycerate of lead was decomposed. In a second experiment the 

 temperature was raised to 145° C, and in a third to 170° C. 

 without better success. Although in the two last cases the 

 heating was continued for two days, the residue which was 

 left after the excess of the iodide of sethyle had been distilled 

 off was inconsiderable, and of a brown unpromising appearance. 

 It was not advisable to employ higher temperatures because the 

 lead-salt decomposes at about 170° C. 



0'535 grm., dried at the ordinary temperature over sulphuric 

 acid, furnished 0'331 grm. carbonic acid and 0"119 grm. water. 



0'53 grm. of the same substance gave 0*277 grm. oxide of lead. 



100 parts contain : — 



Carbon 16-87 



Hydrogen 2-47 



Lead 49*44 



Calculated according to C^ H^ PbO^ :— 



Carbon . . 3 36 17*24 



Hydi-ogen. . 5 5 2*39 



Lead ... 1 103*7 49*71 



Oxygen . . 4 64 



208*7 



The glycerate of lead could be heated to 140° C. without 

 losing in weight or altering in colour; but at 165° C. it turned 

 brown and was decomposed. After having been kept an hour and 

 a half at this temperature, the loss in weight did not amount to 

 two-thirds of an atom of water. Consequently the formula of 

 the anhydrous salt is C^ IP PbO"*. A scries of expei'iments un- 

 dertaken for the purpose of obtaining the sethyle compound of 

 this acid have not yet been successful. How the lead-salt com- 

 ports itself with iodide of sethyle has already been mentioned. 

 The silver-salt could be prepared, but was found so very change- 

 able as to be unlit for further experiments. Some anhydrous 

 glyceric acid dissolved in absolute alcohol, and hydrochloric 

 acid gas passed through the solution, did not yield, either at the 

 ordinary temperature or at 100° C, the desired substance. Nor 

 did the distillation of C^ H'' CaO'' and Ac.K.O, SO^ give any satis- 

 factory results. 



The compounds of glyceric acid are represented by the for- 

 mula C^ IP MC, or, according to the atomic weights used by 

 many chemists, C^ 11^ MO^. The corresponding hydrogen com- 

 pound is C^ H^ 0"* or C® H^ 0**. If glycerine be regarded as a 



