468 Intelligence and Miscellaneous Articles. 



As some of the fatty acids have been believed to unite with water, 

 to form trihydric alcohols, they were elected for examination ; and 

 at the same time hydrated alcohol was also examined, because it 

 could not form a compound with water, and would therefore act as 

 a check upon the results. 



The results of the examination show that formic, acetic, and 

 propionic acids, when mixed with water, do not form new com- 

 pounds, but that the products simply consist of these bodies and 

 water. 



Sulphuric acid in the pure and hydrated conditions was next 

 examined, viz. H 2 S0 4 , H 2 S0 4 +H 2 0, H 2 S0 4 + 2H 2 0, and H 2 S0 4 + 

 3H 2 0. The numbers obtained in this case show that combination 

 takes place chiefly when one molecule of water has been added, only 

 to a small extent in the case of the second addition, and scarcely 

 at all when the third is added ; and the author gives reasons for 

 considering that sulphuric acid combines with one molecule of water 

 only, forming the compound (HO) 4 SO. 



Whilst studying the nature of the hydrated products, the author's 

 attention was drawn to the subject of water of crystallization ; and 

 from the inconsistency as to the presence or absence of water of 

 crystallization in compounds of the same class — as, for example, 

 in those of silver, potassium, and sodium, and also methyl bromide, 

 as compared with analogous compounds — he considers it impossible 

 to believe that water of crystallization has any relationship to 

 chemical combination ; that of course refers to water when it exists 

 as such, and not to hydrogen and oxygen present in the proportions 

 found in water but otherwise combined. If this be so, it is thought 

 that its association with chemical compounds is most likely con- 

 nected with the building-up of the crystalline form, it being diffi- 

 cult to see what other part it can play ; and the reason why some 

 compounds crystallize without and some with water of crystalliza- 

 tion is probably determined by the tendency to produce that form 

 which can be the most readily built up : if that form can result from 

 the anhydrous salt, anhydrous crystals are formed ; if with the salt 

 and water, then the crystals will contain water of crystallization ; 

 and it is well known how change of conditions will cause variation 

 in the proportions of water of crystallization, and also form of 

 crystal. 



These observations would also apply to compounds crystallizing 

 with alcohol, acetic acid, benzene, &c, and to some double salts, 

 where one or more of the constituents would act like water of 

 crystallization. Attention is drawn to the fact that if the above 

 view of water of crystallization be correct, it is evident that a salt 

 containing water of crystallization will be resolved into water and 

 the salt on breaking up of the crystalline form by solution, which 

 is believed to be the case by many who have studied the subject 

 of solution. — The Chemical News, Oct. 22, 1886. 



