CHEMISTRY. (NEW SUBSTANCES.) 



113 



3,559 feet) and at Montanvert (altitude 6,256 feet) 

 considerably more decomposition of oxalic acid by 

 sunlight took place at the higher station, the mean 

 difference being 2.1 to 1 for a difference of level of 

 2,697 feet. The result of the experiments shows 

 that temperature plays a more considerable part 

 than was suspected, but that in the combined action 

 of the two the greatest influence is exercised by 

 light. 



In an experiment described by H. Pillat, a small 

 iron ring was laid directly on the sensitive surface 

 of a bromo-gelatin plate; at its side another similar 

 ring was placed, but separated from the sensitive 

 surface by a very thin sheet of microscopic cover 

 glass. The latter was covered by a bell jar fastened 

 to the plate with paraffin. The whole was left in 

 the dark for four months. After developing the 

 plate it was found that the iron ring under the jar 

 had made no impression, but that the ring placed 

 directly on the sensitive film had produced an 

 image slightly larger than the ring itself, and there- 

 fore extending beyond the line of contact. The ex- 

 periment is interpreted as showing that the phe- 

 nomenon is not due to radiation but to a volatile 

 body produced by the iron. 



Experiments by T. Wiborgh for determination of 

 the reducibility of iron ore indicate that every 

 mineral giving a degree of oxidation of 77.8 at a 

 low temperature will be easily reducible that is, 

 can be transformed into metallic iron by the ordi- 

 nary furnace gas. This degree of oxidation corre- 

 sponds to a particular and definite molecular con- 

 dition, by reason of which no metallic iron is 

 formed till it has been reached ; but as soon as it 

 has been reached the reduction proceeds very 

 rapidly and the degree of oxidation diminishes. 



New Substances. M. Henri Moissan has ob- 

 tained by the direct union of calcium and hydrogen 

 a transparent crystalline hydride, with the formula 

 CaH 2 . The hydride is stable at a high temperature, 

 and is an energetic reducing agent. By its violent 

 decomposition in contact with cold water it 

 strongly resembles the definite crystallized carbide 

 of calcium prepared by the author in the electric 

 furnace. In this compound the hydrogen is com- 

 parable to the metalloids (carbon or phosphorus), 

 and not to the metals. Even the appearance of the 

 hydride distinguishes it from the hydrides of MM. 

 T'roost and Hautefeuille and the hydrogenized 

 palladium of Graham. The author finds that there 

 are in reality two series of hydrides, some in which 

 the hydrogen seems to be in solution in the metals, 

 and the others forming at a more or less eleA r ated 

 temperature, and presenting all the characteristics 

 of definite chemical compounds. 



Besides its curious action on water, M. Henri 

 Moissan says, carbide of calcium acts as a powerful 

 reducing agent, and, by virtue of this property, can 

 furnish a number of new compounds by d'ouble 

 reaction, but only when in contact with the body 

 in a liquid state, or in a state of fusion at a suffi- 

 ciently high temperature. In a state of fusion it 

 acts energetically on the oxides, and if the metal 

 will not unite with carbon as is the case with lead, 

 tin. and bismuth it is set at liberty and can be 

 separated or combined with other bodies, according 

 to the condition of the experiment. If the metal 

 or metalloid is capable of being carburized, a double 

 decomposition takes place according to the for- 

 mula RO + CaC 2 = RrcC + Ca0 2 in which R rep- 

 resents a metal and n a variable number of atoms 

 of carbon. By this method definite crystallized 

 carbides of aluminum, manganese, chromium, mo- 

 lybdenum, silicon, etc., have been prepared. 



Carbide of sodium is obtained by Camille Ma- 

 tignon in the form of a white powder, with-a density 

 at 15 C. of 1.575, and appearing quite insoluble. 

 VOL. xxxvin. 8 A 



Dry air and oxygen have no effect on it at ordinary 

 temperatures, but on gently heating combustion 

 takes place, leaving a residue of CONa s . In the 

 presence of chlorine gas it becomes incandescent, 

 and with bromine the reaction is almost of explosive 

 violence. Iodine has a more moderate action, and 

 C S I 4 , melting at 185 C., can be obtained. Hydro- 

 gen has no action. When thrown into water, 

 carbide of sodium explodes violently, giving a de- 

 posit of carbon. It also becomes incandescent in 

 contact with C0 a and S0 2 . It acts in the cold on a 

 large number of organic substances. The primary 

 and secondary alcohols give off acetylene, giving 

 rise at the same time to a corresponding alcoholate. 



Among other compounds of glucinum prepared 

 by M. P. Lebeau is anhydrous fluoride, which is 

 found in the form of a vitreous, transparent mass, 

 or as a sublimate consisting of very small deliques- 

 cent crystals, melting in a similar manner to glass, 

 but becoming very fluid and notably volatile at 

 800 C ; an oxyfluoride of practically constant 

 composition, an almost transparent white body, 

 completely soluble in water, and a borocarbide, 

 which occurs in brilliant crystals with a metallic 

 luster and a density of about 2.4, which does not 

 change in the air at the ordinary temperature, but 

 oxidizes superficially when heated to redness. The 

 author was not able, in the reduction of glucina by 

 boron in the electric furnace, to obtain any com-' 

 pound free from carbon. 



By the action of hydriodic acid on carbide of 

 glucinum, F. Lebeau has obtained an iodide of the 

 formula G1I 2 in beautiful transparent crystals. 

 The new iodide reacts on a large number of bodies, 

 and serves for the easy preparation of new com- 

 pounds of glucinum, such as the phosphide, the sul- 

 phide, and the cyanide. It also readily unites with 

 organic compounds. 



Heating emerald in a carbon tube in the electric 

 furnace for a few minutes, M. P. Lebeau found that 

 the greater part of the silica distilled off, leaving a 

 melted mass having a metallic luster; this consisted 

 of a mixture of carbide of aluminum, carbide of 

 glucinum, silicide of iron, and silicide of carbon. 

 It, is attacked by dilute acids, giving a solution con- 

 taining glucina and alumina. By using hydrofluoric 

 acid a fairly pure solution of fluoride of glucinum 

 can be obtained at once, fluoride of aluminum being 

 insoluble. If half its weight of carbon is added to 

 the emerald a complete reduction is soon arrived 

 at ; the silica is completely eliminated either by 

 volatilization or the formation of silicide of carbon, 

 a body almost as unassailable as diamond. 



A double iodide of potassium and lead, PbI 9 2KI, 

 has been observed by F. C. H. Brooks, of Queens- 

 land, Australia, to be formed by the addition of 

 an excess of potassium iodide to a lead salt. It 

 occurs in silky, acicular, almost white crystals, and 

 possesses the property of being decomposed by 

 water, with the formation of iodide of lead and 

 potassium iodide. This property makes it a most 

 delicate test for water. It even begins to decom- 

 pose, losing its white color and becoming distinctly 

 yellow, when exposed to the air of a room for a few 

 minutes. It also becomes yellow when gently 

 heated, but assumes its original color on cooling. 

 Heated more strongly, it is partially decomposed, 

 with the appearance of iodine vapors. While pure 

 water decomposes this compound, a strong solution 

 of potassium iodide dissolves it. 



Among the subjects referred to by Dr. Charles 

 Symes in his presidential address at the British 

 Pharmaceutical Conference was the production of 

 sympathetic esters and odorous substances closely 

 related to the odors of flowers, plants, and animal 

 matters. Besides artificial musk, vanillin, and the 

 amyl, butyl, and ethyl compounds resembling fruit 



