156 



CHEMISTRY. (SYNTHESIS.) 



the same. Mr. Thomas S. Gladding has adopt- 

 ed with success a process depending upon pre- 

 cipitation with silver, the fatty salts of which 

 are almost perfectly insoluble in ether, while 

 the resinate is readily and abundantly soluble 

 in it. 



J. Kjeldahl offers a new method for deter- 

 mining nitrogen in organic compounds which 

 depends upon the fact that when a nitrogenous 

 substance is heated with strong sulphuric acid 

 and then oxidized with permanganate of potas- 

 sium, the whole of the nitrogen is converted 

 into the sulphate of ammonium. It is applica- 

 ble to all nitrogenous compounds except those 

 containing the nitrogen in an oxidized condi- 

 tion, or in the form of cyanogen. It is simple, 

 accurate, and expeditious, and is said to have 

 given excellent results in all cases in which it 

 has been tried by the author and by various 

 other experimenters. 



The determination of nitrogen in nitro- and 

 azo-compounds is effected by the addition of 

 some reducing material to the soda-lime, by 

 which the nitrogen is yielded as ammonia. 

 The existing methods Tamm-Guyard's with 

 sodium acetate, Ruffler's with sodium thiosul- 

 phate, and Goldberg's with stannous sulphide 

 and sulphur being somewhat unsatisfactory 

 as general methods, Arnold, after experiment- 

 ing with various substances, has used sodium 

 formate with sodium thiosulphate and soda- 

 lime with excellent results. 



A. Grandval and H. Lajoux describe a new 

 process for the detection and rapid determina- 

 tion of small quantities of nitric acid in air, 

 water, and soils. It depends on the transfor- 

 mation of phenol into picric acid, and on the 

 intensity of the coloration of ammonium pic- 

 rate. To determine a nitrate in solution it is 

 converted into ammonium picrate, and the tint 

 obtained is compared with that of a standard 

 solution by means of a Dubosq colorimeter. 

 By this process the quantity of nitric acid con- 

 tained in a liquid may be determined with cer- 

 tainty to the fifth decimal ; and the process is 

 applicable to very minute quantities. 



Oleve separates the new earth Samaria by 

 fractionally precipitating the mixed nitrates by 

 a dilate solution of ammonia. Samaria con- 

 centrates in the first fractions, from which 

 didymium is separated by repeated precipita- 

 tions, yttria by precipitation with potassium 

 sulphate, and terbia by repeated precipitations 

 with ammonia. The final fractions are nearly 

 white. The atomic weight, as determined from 

 the weight of the sulphate yielded by a known 

 weight of the oxide, is 150. Thalen has 

 mapped 198 lines in the spectrum. The 

 metal samarium has not yet been isolated. 



Charles Tennant Lee, of Boston, employs for 

 the determination of indigo-blue, or indigotin, 

 in indigo, a method by sublimation, which has 

 been uniformly satisfactory. The operation is 

 best effected in a shallow platinum tray, in 

 which dried and pulverized indigo is evenly 

 and thinly spread, and heat applied through 



an iron plate. When the surface of the indigo 

 is covered with a shining layer of crystals, a 

 flat arch of Russia iron is turned over the tray. 

 The purple vapors of indigotin which are now 

 given off condense on the under surface of the 

 arch. When all the crystals ot indigotin have 

 disappeared from the powdered substance, its 

 loss in weight gives the amount of indigotin the 

 specimen contained. 



S. L. Penfield, having observed caesium and 

 other alkalies in a specimen of beryl from Nor- 

 way, Maine, analyzed a number of beryls from 

 different places in Maine, Massachusetts, Vir- 

 ginia, and Siberia, to find to what extent be- 

 ryllium was replaced in them by alkalies. The 

 result was the discovery that, so far as tested, 

 beryls always contain alkalies, although some- 

 times only in small quantities. Sodium and 

 lithium were always present, and caesium oc- 

 casionally, while potassium and rubidium were 

 never detected. 



The director of the Connecticut Agricultural 

 Experiment Station has reported favorably of 

 the results of using simple calcium hydroxide 

 (slacked lime) instead of the mixture of so- 

 dium hydroxide and calcium hydroxide, or 

 oxide proposed by Will and Varrentrapp, as a 

 reagent for converting organic nitrogen into 

 ammonia for the purposes of analysis. 



Synthetic Chemistry. The efforts which have 

 been prosecuted during much of the present 

 century to obtain by artificial means the min- 

 erals occurring in nature have been attended by 

 marked success, especially in France, where 

 well-nigh all the known mineral species have 

 been reproduced by methods often of the most 

 diverse character. MM. F. Fouque and A. 

 Michel-Levy have been working in this field 

 since 1878, and have not only reproduced the 

 minerals as individual species, but have also 

 sought to combine them in their natural asso- 

 ciations, and thus to imitate in the laboratory 

 the processes of nature in the formation of 

 the earth's crust. These authors state as the 

 five conditions which an artificial mineral 

 product must fulfill in order to be a successful 

 synthesis, that (1) it must be identical in its 

 chemical composition with the natural mineral 

 imitated ; (2) the two must also be crystallo- 

 graphically identical ; (3) their internal struct- 

 ure i. e., cleavage, inclusions, etc. must be 

 the same ; (4) the artificial minerals must fol- 

 low the same laws of association as the natural 

 ones; (5) the conditions of the artificial opera- 

 tion must be compatible with the circumstances 

 under which the natural products were formed. 

 The crystalline constituents of the earth's crust 

 are arranged, for purposes of the synthetic stud- 

 ies, in four categories : 1. The minerals of vol- 

 canic rocks i. e., basic rocks; (2) the minerals 

 of acidic rocks, i.e., quartz and orthoclase rocks ; 

 (3) the minerals of the crystalline series, gneiss 

 and mica-schist, for example ; (4) mineral veins. 

 The minerals and their associations of the first 

 of the four categories have nearly all been arti- 

 ficially reproduced by simple fusion ; those of 



