Mixter — Products of the Explosion of Acetylene. 305 



oAo 



Experiment 55. — Gas, 98 per cent of acetylene ; pressure, 

 2*6 atmospheres. The electrodes were 3 mm apart and less than 

 l mm from the glass. The sparking at first produced a filament 

 of carbon between the electrodes. A much stronger secondary 

 current was then applied and after some seconds there was a 

 sudden glow and carbon was deposited 



abundantly in a length of 10 cm of the 

 tube. The explosion did not extend to 

 the gas in the bomb. The residual gas 

 contained 97'5 per cent of acetylene. 



Experiment 56. — Gas, 98 per cent of 

 acetylene; pressure, 2316 mm (3*3 atmos- 

 pheres) at 15°. The electrodes were 4 mm 

 apart and 3 mm from the glass. A moment- 

 ary closing of the primary circuit pro- 

 duced an explosion. The pressure when 

 the gas had cooled to 15° was the same as 

 before the explosion. There were in the 

 glass tube brilliant black rings of carbon 

 separated by spaces less densely coated. 

 Two estimations of acetylene in the re- 

 sidual gas taken at 2 - 7 to 3 "3 atmospheres 

 gave each 1*3 per cent, and two portions 

 taken when the gas in the bomb was at 1*5 

 atmospheres and less gave 1*7 and 16 per 

 cent. 



If the peculiar explosive wave started 

 in the tube extended to the gas in bomb 

 it caused almost complete decomposition 

 of the acetylene. 



As the acetylene used thus far in the 

 work was not free from traces of water, the following experi- 

 ments were carried out in U-tubes such as shown in fig. 3 filled 

 with gas containing 98*8 per cent of acetylene. Some phos- 

 phorus pentoxide was placed in the tube and also a clean piece 

 of phosphorus ; the latter was to remove traces of oxygen. 



Experiment 57. — -The volume of the gas diminished slowly 

 on standing indicating an absorption, but there was no appear- 

 ance of a tarry product. Five days after the tube was filled, 

 the gas, measuring 60 cc , was condensed to 19 cc and then sparked. 

 The explosion was prompt and violent. The condensation was 

 4 per cent and the acetylene in the residual gas was 4 per cent 

 of the gas taken. 



The tube was filled again with acetylene and the phos- 

 phorus pentoxide was made to coat the upper part of it. A 

 piece of phosphorus was placed in the gas. The volume 



