CHEMISTRY. 



Is added, after a few hours a crystalline precipitate 

 forms, which may be collected on a filter, washed 

 with solution of iodate of potassium, dissolved oft' 

 the filter with dilute hydrochloric acid, and, minute 

 as the quantity of calcium present is, it may be 

 shown immediately by the precipitate falling on ad- 

 dition of ammonia and oxalate of ammonium to the 

 strongly acid filtrate. 



In separating calcium from magnesiunij by pre- 

 cipitation of the former by iodate of potassium, it is 

 obviously important, in view of the subsequent de- 

 termination of the magnesium, to know if the 

 presence of iodate of potassium hinders the pre- 

 cipitation of magnesium as magnesium-ammonium 

 phosphate. So far from this being the case, I find 

 that the double phosphate is even less soluble in a 

 saturated solution of iodate of potassium containing 

 some free ammonia than it is in a mixture of two 

 parts ordinary " liquor ammonias " with one part of 

 water. Thus, the addition of solution of iodate of 

 potassium to the ordinary liquid containing phos- 

 phate of an alkali and much free ammonia, over pre- 

 cipitated magnesium-ammonium phosphate, renders 

 the fluid at once opalescent, and occasions an ad- 

 ditional precipitation of magnesium salt. 



I may mention here that I have never met with a 

 specimen of any magnesia or magnesium salt in 

 commerce, although sold as chemically pure, that did 

 not contain a very sensible proportion of calcium. 

 I believe the only available source of a magnesium 

 salt that shall be free from calcium is distilled mag- 

 nesium ; in this, I have never found any trace of 

 calcium. 



Colophthaline and Coloph-Alumina. Under 

 the above names Mr. Paul Curie describes a 

 solid hydrocarbon and a new organic base 

 which he has obtained from common resin 

 (colophony). By a process of distillation at 

 high temperatures, he obtains from this source 

 a much larger proportion of colophthaline than 

 by the ordinary method, and in a form which 

 admits of easy purification. Colophthaline is 

 easily soluble at the ordinary temperature in 

 benzol, naphtha, spirits of turpentine, carbon 

 bisulphide, and ether ; it is dissolved by alco- 

 hol and glacial acetic acid at their boiling-point 

 only, and is deposited again on cooling. The 

 liquid products with which colophthaline is 

 mixed being much more easily soluble in alco- 

 hol, this substance can by this means be com- 

 pletely freed from them. Thus purified, co- 

 lophthaline is a flocculent white body, possess- 

 ing a slight balsamic odor. Its melting-point 

 is at V0 0., and, when melted, its color be- 

 comes brown ; it boils at about 400 0. It is 

 composed of carbon, 93 ; hydrogen, 7 total, 

 100, which numbers correspond to the formula 

 C 22 H 1? . 



Oxidizing agents, chlorine, and nitric acid, 

 attack colophthaline with the greatest facility, 

 forming compounds that undergo a most re- 

 markable reaction when fused with hydrate 

 of potassium. They are transformed into a 

 white amorphous body of decided basic prop- 

 erties, having so nearly exactly the appearance 

 of alumina that it might be easily mistaken 

 for that metallic oxide. For this reason I 

 claim for this new substance the name of 

 ColopJi-alumina, and I will now proceed to 

 enumerate some of its extraordinary charac- 

 teristics. 



Colopli-alumina having been prepared in 

 the manner above described, the fused alkaline 

 mass is dissolved in dilute hydrochloric acid, 

 in which solution ammonia forms a volumin- 

 ous precipitate of hydrate of coloph-alumina ; 

 this white gelatinous precipitate being washed, 

 and left to dry spontaneously, loses the greater 

 part of its water, and shrinks gradually into a 

 compact, hard, stony-looking mass, which still 

 retains 1 equivalent of water, and only loses 

 it at a high temperature. Coloph-alumina is 

 insoluble in all neutral liquids water, spirits, 

 ether, etc. ; it is infusible and non-volatile ; it 

 resists the action of all oxidizing agents, 

 though at a high temperature, and is not de- 

 composed even at 1000 C. by chlorate or ni- 

 trate of potassa ! Owing to the difficulty of 

 decomposing coloph-alumina, it has been found 

 impracticable to effect its analysis by any di- 

 rect method ; its chemical composition, how- 

 ever, as deducted from the mode of its forma- 

 tion, appears to be represented by C3 H 6 O 4 . 



The basic properties of coloph-alumina are 

 not very energetic. Nevertheless hydrochloric, 

 nitric, acetic, and oxalic acids dissolve the base 

 with ease, but the salts thus formed have not 

 been obtained otherwise than in solutions, as 

 by concentrating the liquor the base and the 

 acid are too easily dissociated. 



Concentrated sulphuric acid does not merely 

 dissolve coloph-alumina ; heated to about 200 

 C., it substitutes SO 8 to H, and forms a com- 

 pound which is amorphous and nearly insol- 

 uble in water Sulpho-coloph-alumina, prob- 

 ably C 28 H 4 (SO 8 ) 2 O 4g (HO) ; a red heat mere- 

 ly regenerates coloph-alumina from this. 



Artificial Vanillin. The following is a con- 

 densed description of the process by which 

 vanillin is obtained from the sap of pine or 

 other coniferous trees: Take, 1 . Coniferin ; or, 

 2. The sap of plants mentioned above which 

 has been purified or liberated from albumina 

 or other impurities ; or, 3. An extract of all 

 those parts of the just-mentioned plants con- 

 taining coniferin ; or, 4. The products obtained 

 from coniferin by means of fermentation, pu- 

 trefaction, or similar action ; and treat one or 

 other with oxidizing agents, or such agents of 

 similar action, such as bichromate of potassium 

 and sulphuric acid, or any other peroxide, ox- 

 ide, or acid, or sa-lt, which produce the same 

 effect. The product of the reaction in all these 

 cases is artificial vanillin, which has been proved 

 to be identical in all physical and chemical 

 properties with the aromatic principle obtained 

 by the extraction, etc., of the natural vanilla- 

 beans. 



A New Synthesis of Glycocoll. A new syn- 

 thesis of glycocoll, that is of interest as illus- 

 trating certain fundamental points in chemical 

 theory, has been effected by Emmerling. Hy- 

 drogen iodide exerts upon organic bodies a 

 double action ; it not only reduces them to the 

 saturated hydrocarbon from which they are 

 derived, but also causes them, by assimilating 

 water, to break up into two or more molecules. 



