HISTORY or GEINE. 98 



changed into humin, and humic acid. Tliese are therefore 

 secondary products. Humin, and humic acid, are produced 

 directly, by allowing a free and abundant access of air. 

 Ulmin, and ulmic acid, are then rapidly transformed to 

 humin, and humic acid. Strong acid also hastens this trans- 

 formation, but at the same time changes humic acid to 

 humin. Formic acid is always produced, and distils off 

 during the process ; and also two other new acids. The 

 discoverer of one, was Peligot, in 1828, which Mulder now 

 calls glucic acid, and he himself has added another, produced 

 from this, which is called apoglucic acid. Passing over 

 these, it is difficult to procure the other acids and neutral 

 bodies free from mixture. Whatever may be the quantity 

 of sugar, or the circumstances of the manipulation, it is im- 

 possible to convert more than one-fifth of the sugar into 

 ulmin, and humin, and humic and ulmic acids. The other 

 four-fifths are changed into formic, glucic, and apoglucic 

 acids. 



Having effected the change of one-fifth of the sugar, the 

 ulmic and humic acids are separated from ulmin and humin 

 by potash. Ammonia cannot be used for this purpose. 

 The reason will appear in the sequel. Having separated 

 the several substances, their analysis presents the following 

 results. The proportion per cent, the author has deduced 

 for the greater part from Mulder's formulae. What a chem- 

 ical formula is, will be readily understood from (55). A 

 formula is merely the true expression of an analysis by the 

 number of combining proportions. It presents to the eye at 

 once the constitution of any compound, and affords a readier 

 mode of comparing several bodies like -constituted, than 

 does the proportion per 100 parts. That is added for those 

 whose taste may have led them to omit the details (55). 



But it may here be stated that C stands for carbon, H 



