No. 105.] 433 



Coal of humus is not produced when we evaporate in vacuo at a 

 moderate heat, hence I do not consider it as a regular component of 

 humus, but as an altered humic acid, partially carbonized by heat. It 

 was not produced in any of my researches, where heat was dispensed 

 with. 



In 1839, Peligot described a new acid under the name of glucic 

 acid. My first knowledge of this discovery was from the researches 

 of Mulder, who has made a series of experiments on humic acid, from 

 soil and from the decomposition of sugar. This acid I have also sepa- 

 rated from the sap of the sugar maple tree, and from that of the yel- 

 low and white birch. It exists also abundantly in the brown sugars of 

 commerce, and in beet sugars, and is generally separated in the state 

 of biglucate of lime. It is readily extracted by pouring a small quan- 

 tity of alcohol on brown sugar, which takes up the biglucate of lime, 

 which gives a buff colored precipitate with subacetate of lead. 



It frequently happens that crenic, apocrenic and humic acids exist 

 in brown sugar, and I think they arise from the decomposition of the 

 glucic acid, by the action of ammonia generated in the process of boil- 

 ing the syrup with pearlash or lime water. 



Apoglucic acid exists in the sap of the sugar maple, and is converti- 

 ble into the other organic acids very readily. 



The action of apocrenic acid on vegetation I have examined experi- 

 mentally, by mixing a little apocrenate of potash, (obtained by the 

 decomposition of apocrenate of copper by pure potash,) with pure pul- 

 verized rock crystal, (quartz,) a comparative experiment being made 

 with the quartz and rain water. The result was that green crops of 

 corn, barley, rye, oats and beans, weighed from 4J to 5 times as much 

 when grown in the quartz containing apocrenate of potash, as they did 

 when grown in the quartz with water. The experiment was also tried 

 in test tubes, using solutions, and all the plants tried, absorbed the 

 apocrenate and removed it from the water, diminishing its color. In 

 experiments I find that ammoniacal salts act through the medium of 

 the organic acids most favorably, and have no action in pure quartz, 

 nor even in quartz containing all the mineral salts of plants, no fruit 

 being produced in a single instance unless organic matter was present. 



