THE 



POPULAR SCIENCE 

 MONTHLY. 



SEPTEMBER, 1882. 



ELECTEIC AND GAS ILLUMINATION. 



By C. M. LDNGEEN. 



THE period of contest and denial over the question of the possi- 

 bility of producing a light of low intensity by means of elec- 

 tricity, that would be suitable for the general purposes of interior 

 lighting, has about drawn to a close. It is now pretty generally 

 conceded what there has never been any reason for denying that 

 the known laws of electric transmission interpose no bar to the suc- 

 cessful solution of the problem, but that the difficulties in the way 

 are solely of a practical kind. And it is, further, quite generally 

 agreed that these practical difficulties have been for the most part 

 resolved, and the question reduced down to one of cost simply ; and, 

 while a good deal of discussion has taken place upon this point, but 

 little has been written that will enable the general public to form a 

 judgment upon the subject, and arrive at a trustworthy opinion of the 

 relative cost of it and gas under actual commercial conditions. 



In estimating the relative cost of the two illuminants, it has been 

 common to compare simply the cost of the materials consumed in 

 their production, or, when the cost of the apparatus necessary to 

 generate the electricity has been taken into account, this has usually 

 been upon the basis of a limited production, and, to this extent, 

 unfair to electricity. A comparison, to be of any value, should be 

 between plants of a size sufficient to reduce the cost to the lowest 

 point at which it can be commercially maintained, and should include 

 all of the items entering into it. The attempt has been made, in the 

 following pages, to institute such a comparison, and present the facts 

 in the case as they are, so far as they can be obtained. The compari- 

 son is upon the ib^asis of works capable of producing a million feet a 

 day, as, in such works, gas can be made as cheaply as in any that are 

 vol. xxi. 37 



