246 On the Soundings in the British Channel. 
leeway as muchas possible, her track should be slow but undevi- 
ating, and her constant observations for latitude and longitude 
should be connected by the perpetual log of Gough or Massey. 
The sounding vessels should move in parallel lines to the course 
of the centre ship, there might be three or four of them on each 
quarter, and their precise situation when the lead was at the bot- 
tom, and the line perpendicular, would be ascertained by their 
bearing, and the angular altitude of her mast-head. 
The depth of the water, uniformly reduced either to the mean or 
the minimum of spring-tides, and the nature of the bottom, would 
be the two principal points of inquiry ; but an excellent opportunity 
would be likewise afforded for learning the direction, duration, and 
combination of the tides in the offing, their real rise and fall at a 
distance from the land, and the influence of the Atlantic and Bis- 
cayan currents on the tides, as well as their united effect in trans- 
porting the various deposits from the rivers, by means of which a 
constant accumulation of sand or mud is produced in one place, 
while the rocky bottom is denuded in another. How far the tem- 
perature of the sea is affected by proximity to the land, or by the 
shoaling of the water, and to what cause is to be ascribed the 
mutable colour of the sea, which suddenly varies from light green 
to dark blue, are two amongst several other subjects of research 
which would well deserve the attention of the person employed on 
this service. 
To preserve consistency in the terms used to describe the 
several substances found at the bottom, and which are now 
named with the most amusing caprice, such as crab’s eyes, oat- 
husks, hake’s teeth, §c., every cast ‘of the lead should be regis- 
tered, and the arming cut off and numbered in like manner ; or 
the sand might be separated from the tallow, washed, and folded 
up in papers. These, with all the other data, should be trans- 
mitted to the Hydrographical Office, where they might be laid 
out in their respective situations on the floor of a large room, 
graduated for that purpose, and where they would be easily 
grouped, so as to shew the general arrangement of the districts 
of the sands, gravel, shells, and stones. 
