116 



CHEMISTRY. (NEW PROCESSES.) 



the rod, but in no case will such an accident 

 cause great inconvenience. 



\ method of converting oxide of iron into 

 crystals of hajmatite exhibiting the characteristic 

 forms of the naturally occurring mineral, de- 

 sn-ibed by Prof. Arctowski, of Liittich, consists 

 in passing partially or totally dissociated arnmo- 

 oinm-chlonde vapor over ferric oxide heated to 

 a particular temperature. After a few minutes' 

 exposure to a heat of 600 C. small glittering 

 cry-tals bi'-rin to form; the remainder of the 

 oxide increases considerably in volume, and am- 

 nionium chloride is rapidly absorbed. No fusion 

 occurs, so tliat the absorption is a mechanical 

 one; the ammonium chloride condenses upon 

 the exterior of the particles, eventually convert- 

 ing the powder into a white mass. Upon subse- 

 quent microscopic examination of the white 

 product large numbers of the small brilliant 

 crystals of haematite are observed interspersed 

 among the white particles. When the experi- 

 ment is performed at 700 C. the whole of the 

 ferric oxide is converted into miniature crystals 

 of haematite. It is probable that the ammonium 

 chloride is totally dissociated at this tempera- 

 ture. This method of synthesis of haematite is 

 interesting as throwing light upon the mode of 

 formation in Nature, for the vapors evolved by 

 the fumaroles in volcanic districts always contain 

 a certain proportion of sal-ammoniac, and it is 

 usually observed that the fissures through which 

 these vapors pass are more or less covered with 

 crystals of specular iron and haematite. The 

 chemical action is probably alike in both cases. 



In his suggestions concerning the detection of 

 alkaloids by microchemical methods. Prof. Beh- 

 rens, of Delft, says that a good method must 

 give slides showing the alkaloids pure or in well- 

 crystallized combinations from which the pure 

 alkaloid can be set free by simple and trust- 

 worthy reactions. Such slides can be kept for 

 any time as documents for comparing with stand- 

 ard slides and further experiments, while the 

 color tests in current use generally destroy the 

 alkaloid. Volatile alkaloids are the easiest to iso- 

 late. Thus from 0*3 milligramme of tea and 

 from 1 milligramme of coffee, by extraction with 

 lime water and with alcohol, and subsequent 

 sublimation, characteristic needles of theine were 

 obtained. Cocoa must be extracted with weak 

 acetic acid. After purifying with acetate of 

 lend ami concent rating, the liquid is dried with 

 an excess of sodium carbonate and sublimed at 

 :uo ( '. Powdery theobromine is obtained, giv- 

 ing characteristic prisms with silver nitrate, and, 

 later on. needles resembling theine, more volatile 

 than theobromine, and more soluble in water. 

 Their angle of extinction is 0, and their chloro- 

 mercuraie is easily soluble. For theine the an- 

 gle of extinction is 45, and the chromomercu- 

 rate is thrown down as long needles. Two milli- 

 grammes of cocoa are enough to show both alka- 

 loids. Among alkaloids that are not volatile, qui- 

 nine may be cited, which had been treated by 

 the author >ix months piv ioiisly. As another 

 example, strychnine ami brueine" may be taken. 

 For tracing strychnine, the limit was found by 

 De Vry ami Van dcr Burg at O'OOl milligramme. 

 With the aid of microchemical methods, crystals 

 of strychnine can be obtained down to 0'0002 

 milligramme in the presence of as much brucine ; 



afterward the latter is made to crystallize as 

 chloroplatinate. The actual limit is found at a 

 fourth of this quantity. 



A new method of preparing phosphorus, de- 

 scribed by MM. Rossel and Frank, is based on 

 the use of aluminum as a reducing agent. By 

 this method phosphorus may be obtained directly 

 from any mineral phosphate. Not more than 30 

 per cent, of the phosphorus contained in the 

 mineral phosphate is obtained, however, by the 

 ordinary process, owing to the manner in which 

 the aluminum phosphide developed in it is de- 

 composed. But it is found that the phosphide 

 is totally decomposed by heating with silica, and 

 hence if the mineral phosphate is previously 

 mixed with some form of silica the whole of the 

 phosphorus is liberated, and the reaction pro- 

 ceeds in a regular and readily controllable man- 

 ner. While any ordinary available phosphate 

 may be employed, care must be taken not to use 

 superphosphates containing admixed calcium 

 sulphate, such as are commonly obtained for 

 agricultural purposes by treatment with sul- 

 phuric acid, without separation of the sulphate, 

 for the sulphate is suddenly decomposed by the 

 aluminum, when a certain temperature is reached, 

 with explosive force. 



A general method of artificially preparing 

 crystallized anhydrous silicate similar to the 

 naturally occurring pyroxenes is described by Dr. 

 Herman Traube. It consists in precipitating 

 the particular metallic silicate, sought in anhy- 

 drous crystals, by the addition of a solution of 

 sodium silicate to a solution of a salt of the 

 metal. The amorphous hydrated silicate thus 

 precipitated is heated to a high temperature with 

 boric acid for several hours. When most of the 

 boric acid has volatilized, the anhydrous metallic 

 silicate is usually left in the form of good crys- 

 tals. Ebelmen has already succeeded in arti- 

 ficially preparing the magnesium pyroxene by 

 this method, and Dr. Traube now extends its 

 application. 



The chief feature of the new general process 

 for the preparation of ethers described by Prof. 

 Krafft, of Heidelberg, is the substitution of sul- 

 phonic acid for sulphuric acid as the reagent. 

 This process may be very advantageously sub- 

 stituted for the process now in use. Whereas 

 sulphuric acid is prone to decomposition in con- 

 tact with a readily oxidizable substance like al- 

 cohol, sulphonic acid is stable at the temperature 

 of the ether reaction. Sulphuric acid, more- 

 over, by reason of its great affinity for water, be- 

 comes so diluted during the process that it 

 ceases to be strong enough for further use ; 

 while sulphonic acid does not retain the water 

 which gradually accumulates, but it passes over 

 largely with the ether, and separates from it as 

 a distinct layer in the receiver. With sulphonic 

 acid, therefore, the nrocess of ether making may 

 be carried on continuously for weeks, in open 

 vessels and on a large scale, and there appears 

 to be practically no limit to the amount of alco- 

 hol which any definite amount of sulphonic acid 

 is capable of converting into ether. 



A new method of preparing phosphureted hy- 

 drogen by the direct combination of hydrogen 

 and phosphorus, devised by Prof. Retgers, is de- 

 pendent upon the elevation of the temperature 

 considerably above the melting point of ordi- 



