constructed apparatus set up outside the dwelling-house, as explained in Chapter X., because there would be no air (as in air-gas) in the pipes, &c., and a relatively large escape of carburetted acetylene would be required to produce an explosive atmosphere in a room. Moreover, the odour of the acetylene itself would render the detection of a leak far easier with carburetted acetylene than with air-gas. N. Teclu has investigated the explosive limits of mixtures of air with certain combustible gases somewhat in the same manner as Eitner, viz.: by firing the mixture in an eudiometer tube by means of an electric spark. He worked, however, with the mixture dry instead of saturated with aqueous vapour, which doubtless helps to account for the difference between his and Eitner's results. _Table giving the Percentages by volume of Combustible Gas in a Dehydrated Mixture of that Gas and Air between which the Explosive Limits of such a Mixture lie._--(Teclu). ____________________________________________________________________ | | | | | | Lower Explosive Limit. | Upper Explosive Limit. | | Description of |________________________|________________________| | Combustible Gas. | | | | | Per Cent. of Gas. | Per Cent. of Gas. | |__________________|________________________|________________________| | | | | | ACETYLENE | 1.53-1.77 | 57.95-58.65 | | Hydrogen | 9.73-9.96 | 62.75-63.58 | | Coal-gas | 4.36-4.82 | 23.35-23.63 | | Methane | 3.20-3.67 | 7.46- 7.88 | |__________________|________________________|________________________|