1864. | Fresenius’ Analysis. 373 
former editions. We notice particularly that the organic constituents 
of drinking waters continue to be described under the indefinite titles 
of “crenic and apocrenic acids.” The use of these terms cannot be 
considered satisfactory at a time when they are never employed in 
chemical reports. It must be admitted, however, that the identifica- 
tion of dissolved organic matters, and the determination of their 
amount by quantitative analysis, are still far from satisfactory, and 
constitute subjects urgently requiring further chemical research. 
Again, in the preparation of vegetable ashes for the purpose of iden- 
tifying and determining the mineral constituents of the plant it would 
be good policy to abstain in all cases from applying such a degree of 
heat as will be required from the complete incineration of the organic 
structure, inasmuch as the employment of so elevated a temperature is 
sure to induce the loss by volatilization of a certain proportion of the 
alkaline salts. A more judicious course consists in using no greater 
heat than is required for the complete charring of the organic matter, 
then to extract with water in order to remove the soluble salts, and 
afterwards dry and burn the carbonaceous residue for the purpose of 
recovering the remainder of the mineral salts. 
The work is remarkably well printed, and free from errata. The 
mode of division into chapters and paragraphs, distinctly numbered, 
facilitates reference ; and there is much satisfaction in being informed 
of the authority upon which a statement is made, and the name has been 
generally given between parentheses. A very useful table of weights 
and measures concludes the volume. There are some repetitions to 
be noticed in the analytical details prescribed for the examination of 
simple and of complex substances ; but these are only such as could 
not be entirely avoided ina work devoted to instruction. Altogether, 
we feel strongly disposed to recommend this treatise to the favourable 
notice of the student in chemical analysis; and must remark, in con- 
clusion, that the sixth edition fully maintains the high character of a 
standard work which “ Fresenius’ Analysis” has so long enjoyed. 
VOL. I. 20 
