\ KNTII.ATIMN ANN LKiHTINc; l>t IMMi ( '< >NST I: r< ' I i< >N Jl>i) 



author knows, is the water-works tunnel conduit for the city of 

 Washington, D.C. Col. A. M. Miller, U.S. Engineer Corps, 

 who is in charge of this work, desciihes the method adopted in 

 his annual report for 1899 as follows : 



"It had been the practice to do all work underground by the light of 

 miners 1 lamp- and torches. This means of illumination is very poor for me- 

 chanical work. Tin- fumes and smoke from blasting, added to the smoke from 

 torches and lamps, render the atmosphere underground, especially when the 

 barometer conditions were unfavorable to ventilation, very offensive and dis- 

 comforting to the workmen. An investigation of the subject of lighting the 

 tunnel by other means, more especially at the locality where the mechanics 

 were at work, brick and stone masons, and the workmen on the iron lining, 

 resulted in the selection of acetylene gas as the most available and economi- 

 cal in this special emergency. Accordingly, an acetylene gas plant for 300 

 burners was erected at Champlain-A venue shaft, and one for 60 lights at Foun- 

 dry Branch. The engine-houses at the shafts, the head-houses, and localities 

 in the tunnel, when required, are lighted by these plants. 



Gas pipes were carried down the Chainplain-A venue shaft and along the 

 tunnel both in an easterly and westerly direction, with cocks for burners at 

 proper intervals every 30 feet ; and this system sufficed for illumination from 

 K(M k ('reck to Harvard University, a distance of over two miles. The plant 

 erected at Foundry Branch was in like manner utilized for the illumination 

 from that point in both directions. 



" By connecting with the stopcocks by means of a rubber hose, a movable 

 light, chandelier, or 'Christmas-tree' of any required number of burners is 

 used, thus concentrating the light in the immediate vicinity of the work, and 

 also enabling the illumination to be carried into the cavities or 'crow-nests,' so 

 called, behind the defective old lining. 



" This method of illuminating has proved very satisfactory and quite eco- 

 nomical. It is especially valuable as enabling good work to be done, and 

 facilitating a thorough inspection of the same." 



Electric Lighting. By far the most perfect, and at present 

 the most commonly employed means for lighting tunnel work- 

 ings is electricity. The light furnished by electric lamps is 

 steady and brilliant, and does not consume oxygen or give off 

 offensive gases. The wires are easily removed and extended, 

 and tin- lamps are easily put in place and removed. About the 

 only objection to the method is the fragility of the lamps, which 

 an easily broken by the flying stones and, the concussion pro- 

 duced by Masting. 



