CHEMISTRY. 



139 



passing electric sparks through nitrogen con- 

 tained in a tube at a pressure of less than 0'8 

 of an inch of mercury, a very slow, permanent 

 diminution of the volume of the nitrogen oc- 

 curs. If the tube is heated at 100 C. for sev- 

 eral hours, the original volume is regained. 



New Snbstanets. A curious compound of ar- 

 senious iodide with the hexiodide of sulphur 

 has been obtained by Dr. Schneider, of Berlin. 

 It appears in a dark-gray mass of homogeneous 

 hard and brittle crystals, which yield a reddish- 

 brown powder on pulverization. They can not 

 be preserved in the air, losing all their iodine 

 in twenty-four hours, but can be kept in sealed 

 tubes for any length of time. The compound 

 is of peculiar interest on account of its bearing 

 upon the theory of affinities. The hexiodide 

 of sulphur affords the only known instance in 

 which the supposed six combining bonds or 

 affinities of sulphur are satisfied by monad at- 

 oms; and the natural supposition that it would 

 be eminently ''saturated" is overthrown by 

 this revelation of its capacity to enter into new 

 compounds. 



The compound KF.3HF has been prepared 

 by M. Moissen by combining potassium fluoride 

 and hydrofluoric acid in suitable proportions, 

 avoiding any sudden rise of temperature. On 

 cooling the solution to 23 C., crystals sepa- 

 rated. The crystals are extremely deliquescent, 

 are decomposed by water into the free acid and 

 potassium fluoride, and dissolve in water with 

 production of the most intense cold. If they 

 are suddenly heated with crystalline silicon, the 

 mass becomes incandescent, and a violent dis- 

 engageraent of silicon tetratiuoride gas occurs. 



While experimenting on the production of 

 gelatinous gnn-cotton, F. Nettlewood obtained, 

 by the nitration of alginic acid, a body suffi- 

 ciently elastic on compression but not explo- 

 sive, which gave a brown color when dissolved 

 in water in alkaline solution. The original 

 color of the nitro-alginic acid was bright yel- 

 low, and it was insoluble in water. Unmor- 

 danted cotton dyed a fine Bismarck-brown 

 color, which was fast to soap, more so than 

 many aniline colors, and equaling chrysoidine. 

 Mordanting with alumina or tartar-emetic did 

 not increase the fastness or the depth of the 

 color. The depth of shade was considerable, 

 and could be worked to a great intensity. In 

 an acid solution the dye failed to attach itself 

 to the fiber, ammonia being the best alkali. 



A large number of new aromatic fluorine 

 substitution products have been prepared by 

 Drs. Wallech and Hensler, the properties of 

 which point to some interesting conclusions 

 ling the physical nature of fluorine itself. 

 It is found that in all cases the specific gravity 

 of a compound is raised by the introduction of 

 fluorine instead of hydrogen, while on the 

 other hand the substitution of fluorine is found 

 to have a remarkably small effect in raising the 

 boiling-point. A still more interesting fact is 

 that the difference between the boiling-points 

 of corresponding iodine and bromine substitu- 



tion products, and again between those of bro- 

 mine and chlorine is smaller than that between 

 the substitution derivatives of chlorine and 

 fluorine. While this difference of boiling- 

 points between corresponding bromides and 

 chlorides amounts to from 20 to 23 C'., that be- 

 tween chlorides and fluorides approaches 40 C. 

 This fact, coupled with the small influence 

 which the substitution of fluorine exerts upon 

 the boiling-point, indicates the probability that 

 the boiling-point of free fluorine itself lies very 

 much below that of chlorine (33-5 C.), and 

 that fluorine much more nearly approaches the 

 volatility of hydrogen. Indeed, it appears 

 likely that fluorine is one of the so-called per- 

 manent gases, and might form a worthy object 

 for the attention of those who have been suc- 

 cessful in forcing the other "permanent "gases 

 to reveal their boiling-points. Under all cir- 

 crmstanoes fluorine attaches itself to carbon 

 with far greater tenacity than any of the other 

 halogens. 



Several compounds of silicon tetrafluoride 

 with organic derivatives of ammonia, similar 

 to the body 2X, H s SiF 4 , have been formed by 

 8, Comey and Loring Jackson, of Harvard. 

 One of two compounds with aniline formed by 

 them is remarkable for being insoluble in the 

 usual organic solvents, only alcohol slowly act- 

 ing upon it with decomposition. Brought in 

 contact with water it is at once decomposed, 

 with deposition of silicic acid ; the solution, on 

 evaporation, yields pearly tabular crystals of 

 aniline fluosilicate. aniline fluoride remaining 

 dissolved. Another aniline compound was 

 formed as a white powder, decomposing when 

 warm or when treated with water, and even 

 spontaneously on keeping. 



A new base, theophylline, has been discov- 

 ered by Dr. Kossel in tea, which, while an 

 isomer of theobromine, differs very materially 

 from it in physical and certain chemical prop- 

 erties. Theophylline forms a well-crystallized 

 series ot salts with the mineral acids, and with 

 platinum, gold, and mercury chlorides, and, 

 like theobromine, yields with silver nitrate a 

 silver substitution compound, which is readily 

 soluble in nitric acid. 



A new base and its series of salts, belonging 

 to the group known as "platinum bases." have 

 been obtained by Dr. Hcinrich Alexander, of 

 Konigsberg. The base has the composition 

 Pt(OH) a , 4XH 3 O, and may be considered us 

 the hydroxylamine-platinum compound cor- 

 responding to the free base of the green salt 

 of Magnus. The chloride of the series had 

 been already prepared by Lossen. The free 

 base is precipitated from this salt on the addi- 

 tion of stronger liases, and is perfectly stable 

 in the air, extremely insoluble in water and 

 alcohol, and behaves like a true metallic hy- 

 droxide. The sulphate, phosphate, oxalate, 

 and two interesting isomeric salts, have been 

 obtained. 



A new series of isomorphons double chlo- 

 rides of the inetals of the iron and alkali groups 



