850 



THE POPULAR SCIENCE MONTHLY. 



first volume was noticed in the " Monthly " 

 for November, 1885. The second volume, 

 which is now at hand, is devoted to fixed 

 oils and fats, hydrocarbons, phenols, etc. 

 Somewhat more than half of the volume is 

 occupied by the first of these divisions. The 

 physical characters of the oils are described 

 first, and then the reactions based on the 

 chemical properties. These sections are 

 succeeded by a tabular classification of the 

 oils based on a joint consideration of their 

 origin, physical characters, and chemical con- 

 stitution. Then follow methods of exam- 

 ining fatty oils and waxes for foreign mat- 

 ters and of identifying them, and after that 

 come special methods of assaying some thirty 

 of the principal commercial fixed oils. The 

 next section, on the examination of lubri- 

 cating oils, and that on mineral lubricat- 

 ing oils, which comes later, contain much 

 matter of interest to the mechanical en- 

 gineer as well as to the chemist. Append- 

 ed to this division are descriptions of the 

 chief saponification products of fixed oils — 

 the higher fatty acids, soaps, glycerin, etc. 

 The author has given much personal atten- 

 tion to methods of determining the density 

 of fixed oils, for this property, being largely 

 dependent on the constitution of the oils, is 

 a more or less important means of identifi- 

 cation. He especially recommends the Ar- 

 chimedean or plummet method of taking 

 specific gravities, using Westphal's hydro- 

 static balance. In discriminating between 

 butter and its imitations, he has found the 

 specific gravity test valuable. He also rec- 

 ommends for examining butters the deter- 

 mination of the volatile fatty acids by Rei- 

 chert's distillation process. 



The temperature at which a mixture of 

 the melted fat with glacial acetic acid be- 

 comes turbid on cooling is deemed by him 

 another important indication, but he says 

 that further experience is necessary before 

 the trustworthiness of this test can be con- 

 sidered fully established. 



The accurate determination of glycerin 

 in a complex mixture is a problem which 

 the author does not consider has received 

 a satisfactory solution under all circum- 

 stances. After giving several methods of 

 isolating glycerin in an approximately pure 

 state, available in various circumstances, he 

 proceeds to describe certain processes based 



on the chemical reactions of glycerin. A 

 method originally suggested by J. A Wank- 

 lyn, has been very fully investigated in the 

 author's laboratory, and proved to give very 

 accurate results under certain conditions. 

 This method is based on the oxidation of 

 the glycerin by treatment with permanga- 

 nate in presence of excess of caustic alkali, 

 whereby it is converted into oxalic acid, 

 carbon dioxide, and water. The excess of 

 permanganate is then destroyed by a sul- 

 phite, the filtrate acidulated with acetic acid, 

 and the oxalate determined as a calcium salt. 

 In the presence of foreign bodies yielding 

 oxalic acid on oxidation, the process is evi- 

 dently useless. 



In the second division, after some gen- 

 eral description of the hydrocarbons, the 

 tars of various origins are considered, and 

 then the bitumens. The important com- 

 mercial products derived from petroleum 

 and shale are duly described, after which 

 are taken up the terpenes, benzene and its 

 homologues, naphthalene and anthracene. 

 The properties and methods of assay of 

 monohydric and dihydric phenols are given 

 in the concluding division. The chapters on 

 the aromatic acids and tannins have been 

 deferred to the third volume, which will 

 contain also chapters on coloring-matters, 

 cyanogen compounds, organic bases, albu- 

 minoids, etc. 



The Swiss Cross : A Monthly Magazine 



OF THE AGASSIZ ASSOCIATION. Vol. I, 



Kos. 1 and 2, January and February, 

 1S87. Edited by Harlan H. Ballard. 

 New York : N. D. Hodges, 47 Lafayette 

 riace. Pp. 40 each. Price, 15 cents a 

 number, $1.50 a year. 



The Agassiz Association is an organiza- 

 tion for the practical study of Nature, which 

 originated some ten years ago, under an im- 

 pulse given by the editor of " The Swiss 

 Cross," in the Lenox High-School, Massa- 

 chusetts. Other societies joined the original 

 society to co-operate with it ; and these af- 

 filiated local societies or " chapters " have 

 increased till they number nine hundred and 

 eighty-four, having from four to one hun- 

 dred and twenty members each, of all ages 

 from four years to eighty-four years, dis- 

 tributed in nearly all the States and Ter- 

 ritories, and in Canada, England, Ireland, 

 Scotland, Chili, Japan, and Persia. The 



