0 
all cases taken from the telemeter. In calm weather it was found easy to keep 
the telescopes on vessels moving at the highest speed, but in rough weather the 
electric bells had to be used. Polling and pitching had no effect on the galvano¬ 
meter, nor was the telemeter in any way affected by the discharge of 8-inch guns 
in its immediate proximity. 
In the “ Baltimore ” one telescope is placed forward, the other aft, with a base 
between them of 92 yards. The instruments can be pointed either to starboard 
or port, and turned from one direction to another in about 15 seconds. In 
March last, at Spezia, the Italian ironclad “ Terrible ” (a central battery ship of 
the “ Warrior ” type, only 64 metres long) carried out some practice with Fiske’s 
Automatic Bange-finder with the following results :— 
Range in metres. 
Mean error 
in metres. 
per centage of 
15G5- 
18 
1*22 
1950 
24 
1*23 
2290 
32-5 
1-45 
2978 
68 
1 90 
324.0 
68 
2-10 
3640 
40 
1-10 
* 3880 
28 
•70 
The length of the base was only 58*9 metres. 
The Italian Experimental Committee gave it as their 
would almost have been reduced by half if the base 
would be possible in a modern ship. 
oponion that the errors 
had been 100 metres, as 
III. Position-Finder. 
The Position-Finder sets off the position of an object on a chart, 
two observatories, marked upon the chart, and a central post, where 
is set off, or else simply two observatories as represented in Fig. 8. 
It comprises 
the triangle 
Each obser- 
Fig. 8. 
A 
/T\ 
/ \ 
vatory has a telescopic needle attached by a Wheatstone’s Bridge to a simple 
needle at the central post. These two needles are placed upon the precise points 
of the chart which correspond to the two observatories. The telescopes being 
laid on the object, the needles at the central post are turned by hand till their 
25b 
