210 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. [94] 



mounted on the fan-sliaft without the intervention of any mechanism 

 whatever. The plant is suspended from the under side of the main-deck 

 beams in the boiler-room. The air-opening of the fan is circular, and 

 has a diameter of 14 inches, which is the size of the main conduit. The 

 two main branch conduits, one on eacb side of the ship, are 11 inches 

 in diameter, and their branches, which run fore and aft the entire length 

 of the ship, commence with a diameter of 9 inches, and diminish in size 

 as they recede from the branch mains until a diameter of 3 inches is 

 reached at the extremities of the hull. The registers are uniform in 

 size, and have an opening of 2^ inches. These openings are regulated 

 by rotary covers on ground faces, whereby they are made air and water 

 tight. The conduits are galvanized-iron spiral pipes, light, and strong 

 enough to bear an internal pressure of 60 pounds. The pipe-joints are 

 riveted and soldered. The system was designed to run at 1,018 revolu- 

 tions per minute, and at that speed 251,500 cubic feet of air would have 

 been exhausted from the ship, or a mean of 3,007 cubic feet per hour 

 for each of the 75 persons on board. This, in actual practice, has not 

 been realized, howevjBr, from lack of power in the motor driving the 

 fan ; in fact, not much more than half this volume has been reached. 

 ^Notwithstanding this, the air in the inhabited parts of the ship is much 

 better than it could possibly be without the artificial ventilation, and 

 the comfort and health of all is thereby promoted. The vitiated air 

 gathered from all parts of the ship is brought, by the system of pipes 

 and conduits already described, to the upper part of the fire-room, 

 where it is discharged with considerable force, and then mingles with 

 the air entering the furnaces. Judging from my own experience during 

 the past year, and from talking with various officers attached to the ship, 

 I think there is but little doubt that the air between decks has been 

 best, and every one has felt most benefit from the artificial ventilation, 

 when the system has run continuously for hours at a time, thus pre- 

 venting any accumulation of vitiated air, than when it has been run 

 spasmodically, even though a higher rate of speed was maintained for 

 a short time. 



Lighting. — The ship is lighted by the Edison incandescent system, 

 using a Z dynamo of 51 volts pressure, and requires about six horse- 

 power from a steam-engine. The current of electricity flows through 

 carbon filaments in vacuo, of 69 ohms resistance in lamps, each of which 

 gives a light equal to 8 candles' power. Some 16-candle lamps are now 

 in use on board. The total number of lamps in the ship is 140. Each 

 state-room is supplied with one. The lamps are mounted on brackets 

 and fixtures resembling gas-fixtures, and are lighted and extinguished 

 by a key, which is much like the stop-cock on a gas jet. The lamps are 

 guaranteed to last for 600 hours ; many of those in this ship have been 

 m use since the ship was commissioned, and have burned more hours 

 than they were guaranteed to do. One of them has burned 1,590 hours ; 

 several have burned more than 1,200 hours, and the average life has 



