far the purposes of Illumination in Lighthouses. 69 



Although, therefore, I cannot claim the merit of first re- 

 commending its introduction, I am desirous of having the 

 greater honour, of being the means of bringing it into general 

 use, by placing before the public eye its numerous and palpable 

 advantages. 



There can be no doubt that oil-gas is preferable to coal-gas ; 

 but the methods of manufacturing and purifying the latter have 

 been brought to such perfection, that its cheapness far more 

 than compensates its inferior illumination. I shall therefore 

 suppose, that the gas to be used is made from canneh coal, pu- 

 rified by the most approved methods. 



Mr STEVENSON informs us, that, about 1810, it was proposed 

 to alter the lighthouse of Inchkeith, from an oil to a gas light : 

 " But upon inquiring into the state of the expence of the appa- 

 ratus, and other circumstances connected with this plan, it was 

 found that the adoption of the proposed alteration would not be 

 an object in point of economy. The gas-light, in this instance, 

 was disapproved of by the Scotch Board, chiefly from the appa- 

 rent uncertainty which seemed to attend the regular and con- 

 stant exhibition of those lights." Whatever may have been the 

 character of these objections in 1810, they have now no force, as 

 the economy and regularity of gas-lights have been established 

 by the experience of thousands. A single lighthouse-keeper is 

 perfectly able, in the time that he would spend in cleaning his 

 lamps, to manufacture the best coal-gas from cannel-coal, at the 

 expence of less than Jive shillings for every 1000 cubic feet, where- 

 as the same quantity of oil-gas is now sold from the pipe atjifti/ 

 shillings, and compressed oil-gas at eighty shillings *. Economi- 



' The economy in oil, in wicks and in lamps, must be very considerable, and, 

 were it necessary, might be easily valued. In lighthouses which are near towns where 

 gas is compressed, and to which it could be sent by sea-carriage, portable gas might 

 be introduced with the most obvious advantage. 



