1815.] Elements of Organic Nature are comluned. 263 



on a filter, washed it with boiling water, and dried it in a vacuum. 

 This substance is a new combination of sugar and oxide of lead. 

 It is quite insoluble in water, light, white, and destitute of taste. 

 The acids, even carbonic acid gas, separate the sugar from it. 

 When heated to a certain point it takes fire, and continues to burn 

 of its own accord, leaving as a residuum oxide of lead mixed with 

 metallic lead. It appears to contain no combined water. 1 have 

 not been able to procure this substance quite tree from carbonate of 

 lead ; but it is easy to determine how much of it is present by dis- 

 solving it in acetate of lead, which docs not act upon the carbo- 

 nate. By this means I found that, in the subsaccharate of lead 

 employed in my experiments, there was 1-,V per cent, of carbonate 

 of lead ; for 10 parts dissolved in acetate of lead left 0*15 of car- 

 bonate of lead undissolved. 



Two parts of the subsaccharate of lead, wh«n burnt, left 

 ri7-8 of oxide of lead; but we must subtract 003 for carbonate 

 of lead, that is, 0*025 of oxide of lead, and COS of carbonic 

 acid. There remains ri47B for the oxide of lead, and 0*S222 

 for the sugar; so that the subsaccharate is composed of 



Sugar 4174 100 



Oxide of lead 5S-2G V3i)'6 



100-00 



I repeated this analysis several times, and the results varied be- 

 tween 138 and 140 of oxide combined with 100 of sugar. The 

 reason of this variation seems to be the difficulty of discovering 

 when the oxide of lead is entirely penetrated with sugar. When 

 any of it remains uncombined, it is obvious that the analysis will 

 give an excess of base. The oxvgcn of 131) -6 of oxide oi' lead is 

 'J-HH. 



If we digest the above-mentioned subsaccharate in a solution of 

 sugar, a part of it dissolves, and forms a clear liquid, witii a slightly 

 yellow colour, which contains lead. But the quantity ol' this metal 

 is very small when compared with that of the sugar, of which the 

 solution appears to contain an excess in the form ofsupei-saccharatc. 

 When evaporated it leaves behind it a syrupy mass, which docs not 

 crystallize, and which attracts humidity from the atmosphere. 



The crystalline form of sugar docs not lead us to suspect tiiat it 

 contains water. I reduced it to a fine powder, and dried it in a 

 vacuum. The loss of weight was only 1 per cent. 1 took ten 

 parts of this sugar, and mixed them with 40 |)arts of yellow oxide 

 of lead, reduced to a fine jjowder, and heated to redness after- 

 wards. I digested this mixture in water. In the heat of a water- 

 bath, till the oxide of lead had absorbed all the sugar. J then put 

 it into a vacuum and dried it. The loss of weight was 053. 1 

 then heated it to 212'^ in a vacuum ; but it sustained no farther loss 

 of weight. This loss must have been water combined with the 

 ^ugar; for, on dissolving the saccharalc in nitric acid, not a sinuk- 



