IB26.] f>f Carbon and Hydrogen, SfC. 47 



The general process, which appears to me to be the best 

 for the preparation of this substance only, is to distil a portion 

 of the fluid deposited during the condensation of oil gas, to set 

 aside the product obtained before the temperature rises to 170°, 

 to collect that which comes over by 180°, again separately that 

 which comes over by 190°, and also the portion up to 200° or 

 210°. That before 170° will upon redistillation yield portions 

 to be added to those of 180° and 190°; and the part obtained 

 from 190° upwards will also, when redistilled, yield quantities 

 boiUng over at 180°, 190°, 8cc. Having then these three por- 

 tions obtained at 180°, 190°, and 200°, let them be rectified 

 one after the other, and the products between 175° and 195" 

 received in three or four parts at successive temperatures. Then 

 proceed with these as before described. 



It will sometimes happen, when the proportion of bi-carburet 

 of hydrogen is small in the liquid, that the rectifications must 

 be many times repeated before the fluids at 185° and 190° will 

 deposit crystals on cooling ; that is to say, before sufficient of 

 the permanently fluid part at low temperatures has been re- 

 moved, to leave a solution so saturated as to crystallize .at 0°. 



Bi-carburet of hydrogen appears in common circumstances 

 as a colourless transparent liquid, having an odour resembling 

 that of oil gas, and partaking also of that of almonds. Its 

 specific gravity is nearly 0*85 at 60°. When cooled to about 

 82° it crystallizes, becoming solid ; and the portions which 

 are on the sides of the glass exhibit dendritrical forms. By 

 leaving tubes containing thin solid films of it in ice-cold water, 

 and allowing the temperature to rise slowly, its fusing point 

 was found to be very nearly 42° F. ; but when liquid it may, like 

 water and some saline solutions, be cooled much below that 

 point before any part becomes solid. It contracts very much 

 on congealing, 9 parts in bulk becoming 8 very nearly ; hence 

 its specific gravity in that state is about 0-956. At 0° it appears 

 as a white or transparent substance, brittle, pulverulent, and of 

 the hardness nearly of loaf sugar. 



It evaporates erMrely when exposed to the air. Its boiling 

 point in contact with glass is 186°. The specific gravity of 

 its vapour, corrected to a temperature of 60°, is nearly 40, hy- 

 drogen being 1 ; for 2'3 grains became 3-52 cubic inches of 

 vapour at 212°. Barometer 2998. Other experiments gave a 

 mean approaching very closely to this result. 

 It does not conduct electricity. 



This substance is very slivhtly soluble in water; very soluble 

 in fixed and volatile oils, in ether, alcohol, 8cc. ; the alcoholic 

 solution being precipitated by water. It burns with a bright 

 flame and much smoke. When admitted to oxygen gas, so 

 much vapour rises as to make a powerfully detonating mixture 



