200 Dr. Debus on the Action of Nitric Acid on Ghjcerine. 



from the motlicr-liquor by means of filteving-papcr, were dried 

 over sulphuric acid at the ordinary temperature. 0-377 grni. 

 gave 0*114 grm. chloride of potassium. 



In 100 parts ;— 



Found. Calculated. 



C^IPKO^+C^HOO'. 



Potassium . . 158 15-8 



If this substance be really biglycerate of potash, it ought to 

 decompose one equivalent of carbonate of lime, and give rise, 

 for each equivalent of potassium it contains, to the formation 

 of one equivalent of glycerate of lime. 



0-584 grm. of the supposed biglycerate of potash vi^as dis- 

 solved, and the acid solution neutralized with pure carbonate of 

 lime. After boiling it for some time and then filtering it from 

 the undecomposed carbonate, the dissolved lime was precipitated 

 from the filtrate with oxalate of ammonia and converted by the 

 usual method into carbonate of lime. Thus 0-119 grm. of 

 the latter, corresponding to 0-047 grm. calcium, was obtained. 

 Since, according to theory, 250 parts of C^ H^ KO* + C^ lis 0" 

 ought to dissolve a quantity of carbonate of lime containing 20 

 parts calcium, therefore the above 0-584 grm. substance taken 

 should dissolve 0*046 grm. calcium in the shape of carbonate. 



Found. Calculated. 



Calcium . . . 0-047 0046 



From these determinations it follows that the compound in 

 question is biglycerate of potash, and the formula expressing 

 its composition = C^ H^ KO'' + C^ H^ 0". 0-408 grm. of the 

 same was kept for two hours at a temperature of 105° C. ; it 

 melted to a clear, transparent, colourless liquid, and lost in 

 weight only 0-005 grm. The same quantity of substance ex- 

 posed for two hours to 135° C. lost 0-028 grm. The salt had 

 assumed after this treatment a brown colour, and was partly 

 decomposed. The compound C^ H^ KO^* + C^ H^ 0^ seems there- 

 fore not to contain water of crystallization. 



Glycerate of Lime, C^ H'^ CaO* -f H^ 0. 

 This compound crystallizes in small shining crystals, which 

 frequently resemble lactate of lime in appearance. But if 

 both are viewed by means of a microscope, a striking differ- 

 ence is recognized. Glycerate of lime consists apparently oi 

 rhombic plates, and lactate of lime of needles. The crystals of 

 C^ H^ CaO"* -f- H^ dissolve easily in hot and cold water, but 

 not in alcohol. Between 130° and 140° C. they melt, and lose 

 quickly one atom of water ; on dissolving the substance after 

 this treatment in water, the original salt, C^H.-^CaO'*-f H^O, 



