328 Mixter — Partial non-explosive Combination of 



L. Meyer and Seubert* observed at the same pressure that 

 three-fourths of the gas combined. The writer noticedf 

 that weak sparks did not cause an explosion of the gas. This 

 is not peculiar to detonating gas, as Dixon % states that " The 

 explosion of cyanogen and oxygen depends solely on the nature 

 of the spark. A strong spark causes the mixture to explode 

 violently, whether wet or dry. A weak spark may be passed 

 through the mixture, wet or dry, without apparent effect." 



Emich§ has recently studied the inflammability of thin layers 

 of explosive mixtures of gases, and has found that the length 

 of the spark required for ignition bears an inverse relation to 

 the density, and that the addition of oxygen to detonating gas 

 till it is to the hydrogen as 1 : 1 increased the sensitiveness of 

 the mixture to sparks ; an analogous fact obtains for an explo- 

 sive mixture of hydrogen and chlorine. On the contrary, 

 equivalent mixtures of carbonic oxide and oxygen are more 

 sensitive than those containing an excess of either. 



The glow discharge of electricity produces gradual combina- 

 tion of explosive mixtures.! Meyer and Raum^f experimented 

 with detonating gas in sealed bulbs, and observed no percepti- 

 ble combination after exposure for 218 days, to a temperature 

 of 100°, while after 65 days, at 300°, they found in three tests 

 that 9*5, 0*4, and 1*3 per cent of the gas had united. They 

 obtained at 350° and 50 hours, 1*6 per cent, and after 120 

 hours, 1*9, 16'4, 0*5, 0*7 per cent. Kranse and Meyer** found 

 that 28 to 100 per cent of detonating gas combined when 

 heated to 518° for 2 hours, in sealed bulbs. On the other 

 hand, Askenasy and Meyerff observed that but little water was 

 formed where the gas passed slowly through a vessel at 606°. 

 Freyer and Meyer J J determined the temperatures at which mix- 

 tures of gases exploded when slowly passing through a hot 

 vessel, and also when quickly heated in sealed bulbs. Explo- 

 sions occurred at the higher temperatures given in the follow- 

 ing table, but not at the lower : 



With free In sealed 



current. bulbs. 



650-730° 518-606 c 



with 650-730° 606-650 c 



oxygen 606-650° 518-606 c 



Hydrogen 

 Methane 



Ethylane f required 606-650° 518-606° 



Carbonic oxide j for complete 650-730° 650-730° 



Hydrogen sulphide J combustion 315-320° 250-270° 



Hydrogen and Chlorine 430-440° 240-270° 



* Jour. Chem. Soc, xlv, 587. f This Journal, iv. 51. 



X J Chem. Soc., xlix, 384. § Monatsheftf. Chem., xviii, 6, xix, 299. 



I This Journal, iv, 51, 1897. ^ Ber. d. deutsch. Gesell., xxviii, 2804. 



-'•-* Licbig's Ann., cclxiv. 85 ff Liebig's Ann., cclxix, 49. 



tt Zeitschr. fur phys. Chem., xi, 28. 



