94 M. Daniel Colladon’s Experiments on the Production 
in a diving-bell, only confused sounds are heard, without the 
articulations being distinguishable at the distance of a few 
metres. 
The shock of a waterfall, or the action of the paddles of a 
steam-boat of a hundred horse-power and upwards, produces 
only a faint and confused sound under water, a kind of slight 
humming, at the distance of 50 metres. The wheels of a 
steam-boat produce, under water, a sound analogous to the 
humming of a bee; and at the distance of 1000 metres no dis- 
tinct sound whatever is heard. I am therefore inclined to 
think that it is a mistake to allege, as has been so often done, 
that the noise of steam-boats has the tendency to drive fishes 
from the rivers. 
Although the sounds transmitted by water, and made sen- 
sible by means of my apparatus, are of much shorter duration 
than tho-e transmitted by the air; yet we determine with the 
greatest facility, not only the degree of acuteness and the 
musical value of the sound, but also the tone of the body 
struck; very frequently we can guess at its nature, and, to a 
certain point, its dimensions and the manner in which it has 
been struck. The noise of a chain moved under the water is 
so distinetly perceptible, that it may be known when a vessel, 
3000 or 4000 metres distant, raises her anchor. In maritime 
warfare this observation may prove of some importance. 
I have pointed out, in the memoir quoted, the influence of 
sereens in diminishing the intensity of transmitted sound. This 
influence is not absolute; if the vibrations are energetic, the 
sound is transmitted with a certain intensity beyond the solid: 
obstacles it encounters. In an experiment made with a large 
bell, each stroke was reckoned in a house built at the edge of 
the water on an embankment, at a distance of about 3000 
metres from the bell, although the latter was separated from 
the house by a promontory: the sound seemed to issue from 
the foundation of the pillars of the walls. A bell weigh- 
ing 500 kilogrammes, belonging to one of the churches of the 
Canton of Geneva, was placed at my disposal for a few days. 
It was suspended to an apparatus placed on a vessel, by means 
of which it was easy to sink it in the water and draw it up 
again. It was sunk to the depth of three metres, in a place 
where the water was about fifteen metres deep ;-to strike it a 
