( 338 ) 



From this it is clearly seen that starting Iroiu 39° the velocitij of 

 electrical reaction rapidly increases, reaching a maximum at about 9" 

 and then diminishing again. 



It is worthy of note that the curve, which here represents the 

 velocity of' electrical reaction at different temperatures, possesses the 

 same form as that representing the rate of crystallisation of many 

 substances at temperatures below the melting-point '). I shall take 

 up this subject more fully later, as also the study of the velocity 

 of the following reactions: 



Zn + CuSOi =Cu +Zn804 (I)ANlELL-elenient). 

 Zu + Ilga SO.i = Hg-o + Zn SOj, (Cl AUK-elcnient). 

 Zn + 2x\gCl ^Ago + ZnClo (Wakkkn de la RuE-clement). 

 Zn + 2 Hg Cl — Ug2 + Zn CU (Hklmiiültz clenicnt). 

 Amsterdam, February 1899. 



Chemistry. — Prof. Fkanchimont presents to the library of the 

 Academy the dissertation of Mr. L. T. C. Schey entitled : 

 „C« syntheticaUij prepared neutral (jlyceryl-ethereal salts — 

 triacylins — of saturated monobasic acids with an even fiumber 

 of C-atoms'" and elucidates it in the following words : 



Since Chevreul's experiments in the first quarter of this century, 

 fats, at least animal fats, are considered as mixtures of glyceryl-ethcreal 

 salts, on account of the products formed by them after treatment with 

 solutions of bases; but it is extremely rare that a glyceryl-ether has 

 been extracted from it in a pure form. The difficulties attached 

 to such separations have as yet not been sufficiently overcome. 



About the middle of this century some of these glyceryl-ethereal salts 

 have been made synthetically by Berthelot and others, but generally 

 they did not obtain them in a pure condition. Now Mr. Öchey has, 

 with a view to the acids said to have been obtained from butter, made 

 synthetically eight glycerides, called by him, in order to prevent 

 confusion with polyglyccrindcrivatives, triacylins and Ikjs determined 



') See (iEliNKZ, Joiinijil de |iliysi(|iic (2) +, (18S5) p. öl'.i. 'J'amman, Zfitsdirift 

 fiir ]ili)'s. Chemie, u. ;i. X'.'J, "H't (1888). v "t IIokk, \'(iiiesiiii^cii ulier tlieur. uiul 

 plivs. Chemie (1898). b. Hu. 



