40 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. [38] 



As the engine and dynamo are run by a coal-heaver in addition to 

 other duties, the writer has not entered the item of wages. 



As the price of the lamps has been reduced 15 per cent, and the price 

 of fixtures continues to diminish, we have no doubt that the running- 

 expense of the light will grow less. During 1884 we paid as high as 

 $18 a ton for coal, at Aspinwall, and in 1883 as low as $3.93 a ton, at the 

 Norfolk navy-yard. Between such ranges the cost of the light must vary, 

 but as the writer has included all the coal consumed on board for that^ 

 purpose during the entire period of the ship's existence, he believes the 

 mean will be found to be very close to the correct one. 



A correct average number of lamps cannot be ascertained where they 

 are being turned on and off by so many persons, but the writer's aver- 

 age, taken from a number of observations, places the number at 47^. 

 Assuming this to be correct, the cost of the light in candles-power x^er 



66597 



hour becomes ---_—-— — - . ^ ^^ ^„^ — - = .05707 cent. 



(1592.75+1481.5) 47^x8 



This is about 38 i^er cent more than the cost of an equivalent amount 

 of gas-light in Washington City, where coal costs less than $5 per ton. 



DEEP-SEA LAMPS. 



Our deep-sea cable is 940 feet in length and is coiled upon a reel, 

 from which it may paid out to any depth within that limit. The lamps 

 are according to Edison's patent, but the wires simply extend through 

 the bottom of the lamp, the ends being free. We solder these wires to 

 our cable, insulate with gutta-percha, tape, and "insulation compound.'' 

 The lamps are of about 42 ohms resistance and are about 16 candle- 

 power. The lami)s burn quite well under water and can be seen very 

 plainly at moderate depths, but they disappear entirely when 70 feet 

 below the surface. We have had the deep-sea lamp down about 750 

 feet. There are two other submarine lamps, having each about 40 feet 

 of cable with attachment plugs, so that they can be attached to any 

 lamp socket. These have been used by the naturalists, who immerse 

 them a few feet beneath the surface of the water to attract marine ani- 

 mals; 'by this means they have secured squid in large numbers, amphi- 

 pods, silver-sides, young bluefish, young lobsters, and fiying-fish, and 

 dolphins have been seen to a]jproach these lamps. 



WABMINa AND VENTILATING. 



Experiments made by the writeron two wooden ships of the Navy show 

 that 1 square foot of steam " radiator" surface is sufficient to warm 1 

 cubic foot of space on shipboard, even in the coldest weather, and he em- 

 ployed that rule in proportioning the steam radiators for the Albatross. 

 The simplest forms of radiators were adopted, and we find, in practice, 

 that they are quite as " noiseless " as the patented radiators, when prop- 

 erly piped for draining. In the pilot-house we adopted a plain return- 



