WITHOUT THE USE OF THE SOUNDING-LINE. 
689 
in lat. 48° 44' N., long. 44° 44' W., or at a point 25 nautical miles removed from the 
place where it was supposed to have been lost (see Plate 63. fig. 3). If complete infor- 
mation regarding the depth of the Atlantic Ocean had been available in laying the cable, 
and if the steam-ship ‘ Faraday ’ had at that time been furnished with a reliable 
bathometer, the uncertainty regarding the position of the vessel when the cable was 
buoyed would never have arisen, and much anxiety and time would have been saved 
in recovering the end. In cable-laying a bathometer is more particularly of use, because 
the amount to which the retarding-brake has to be weighted bears a definite relation 
to the depth of sea traversed ; . and an accurate knowledge of that depth is essential to 
prevent either loss of cable from excessive slackness, or permanent danger through an 
insufficiency. 
A bathometer of careful construction would be extremely useful in increasing our 
knowledge of the depth of the ocean, whilst instruments of inferior accuracy would 
serve the useful purpose of furnishing the navigator with timely warning of approaching 
shallows. 
It is chiefly with a view to this latter result that I venture to place my inquiries into 
this subject before the Royal Society. In doing so I wish to acknowledge the valuable 
assistance I have received from Mr. B amber and Dr. Higgs, the former having conducted 
the experiments to determine the influence of temperature on the elasticity of springs, 
and effected the adjustment of the instruments on land, while the observations on 
board ship were taken by Dr. Higgs. 
Addendum. — On an Attraction-meter. 
Received February 23, 1876. 
At the reading of the foregoing paper, I exhibited an instrument for measuring 
horizontal attractions, which, at the same time, illustrates the action of the bathometer. 
This instrument (Plate 65) consists of a horizontal tube of wrought iron 400 millims. 
long, terminating at each end in a horizontal transverse tube of cast iron of 60 millims. 
diameter and 300 millims. long. The first-named horizontal tube is partially closed at 
its ends, and communicates with the transverse tubes below their horizontal mid 
section. The transverse tubes communicate also by means of a horizontal glass tube of 
2 millims. diameter at a superior level to the former. 
The whole apparatus being mounted upon three set-screws is filled to the level of 
the half-diameter of the transverse tubes with mercury, which mercury fills also the 
whole of the longitudinal connecting-tube ; the upper halves of the cast-iron transverse 
tubes and the glass connecting-tube are filled with alcohol tinted with cochineal, com- 
mdccclxxvi. 5 c 
