390 Dr. Turner's Chemical Examination of the Fire Damp 



a production of water corresponding to the quantity of explosive mixture 

 so introduced, without the production of any carbonic acid. But if carbonic 

 oxide or olefiant gas were present, then cold spongy platinum would 

 not act at all, a small proportion of explosive mixture being employed, and 

 if the action were forced by using hot spongy platinum, or by the free in- 

 troduction of explosive mixture, then would carbonic acid, as well as water, 

 be generated. 



To apply these facts to the case in point, some very active platinum balls 

 of the size of j)eas, were made from a mixture of pipe clay, spongy platinum, 

 and the yellow ammoniacal chloride of platinum, the materials being mixed 

 with water so as to form a plastic mass, which, after receiving the required 

 size and form, was gently dried, and ignited for an instant before the blow- 

 pipe,* and were introduced into the gaseous mixture over mercury, sometimes 

 cold and at others warm, ten or twenty seconds after incandescence. Their 

 action, on all the samples of fire-damp, was precisely of the same character 

 with fire-damp, oxygen being previously added or not, the platinum balls, 

 whether cold or warm, were completely inactive. On adding some explo- 

 sive mixture to the fire damp, the platinum balls acted readily to their full 

 extent. To give some instances — 



I. With fire-damp from the yard coal seam Burraton Colliery, the specified 

 gravity of which was O600. 



With 46'5 measures of this gas, and 12'5 of explosive mixture, a plati- 

 num ball, nearly cold, caused, in ten minutes, a loss of volume equal to 12 

 measures. 



In a second trial the loss in ten minutes was 13 - 6 in a mixture of 49 

 measures of fire-damp, and 14 - 1 of explosive mixture. 



77. With fire-damp from the Bensham Coal Seam, Wallsend Colliery, 

 the specific gravity of which was 0'6024. 



In a mixture made with 34"3 measures of fire-damp, and 13"1 of explo- 

 sive mixture, a platinum bail introduced warm, caused, in six minutes, a 

 loss of volume equal to 12*4 measures. 



* Before use the little balls were always ignited. 



