BULLETIN OF THE UNITED STATES FISH COMMISSION. 157 



When using 45 lamps we get 7.77 per indicated horse-power; when 

 using 50, we get 8.5 per indicated horse-power; and when using 70, we 

 get 10.11. We have not, to my knowledge, ever used more than 70 

 lamps at one time, though there are 140 in the plant. The average 

 number of lamps in daily use is about 47,* for which purpose we con- 

 sume about 21 jwunds of coal per hour, and use, on an average, two- 

 thirds of a gill of oil. Since November we have been using a light oil 

 manufactured by the Vacuum Oil Company of New York, and find that 

 we can run our light machinery with a smaller quantity. As this oil is 

 used on the exhaust fan as well as the dynamo and its engine, it is im- 

 possible to say what proportion each machine receives ; but from short 

 experiments I conclude that the dynamo and its engine (when the 



Fig. 8. 



journals are in good order) will use about one-half a gill per hour. 

 Assuming this to be correct, the cost of running the lights for the year 

 has been as follows: 



The dynamo was in operation 1,592 hours and 45 minutes, during which 

 time the consumption of coal for this purpose was 14 tons 2,082 pounds, 

 at a total cost of $08.67. 



The oil used during the same period and for the same purpo83 is es- 

 timated to be G7 gallons, the mean cost of which was 72^ cents per 

 gallon, making the total cost for oil $48.57. 



The cost for repairs, preservation, and restoration has been as fol- 

 lows : 



2 K brushes, at $2.50 $5 00 



4 Z brushes, at $1 4 00 



2 cut-out blocks, at 32 cents 64 



*As lamps are so frequently turned on and off in different parts of the ship, at all 

 hours, it would be impossible to keep an accurate record. 



