TEMPERATURE AND MOVEMENTS OF THE DEEP SEA. 
123 
the bottom of the ocean at different depths, but also of different 
portions of the column of water in going down to the bottom. 
This we ascertained by letting down our thermometers to a 
certain depth, and then taking them up ; then letting them 
down to a greater depth ; and so on. In that manner we got 
what I term 44 serial soundings ” — that is, a series of temperatures 
of different depths in the same spot ; and those corresponded very 
closely indeed with the bottom temperatures that we got at like 
varying depths. As a rule, the lowest temperature was always 
the bottom temperature. I shall presently explain to you how 
this comes to pass. 
Our first expedition was a very short one. We had very bad 
weather in a very stormy region, between the North of Scotland 
and the Faroe Islands, and we were not able to make many 
soundings or many dredgings ; and yet, by a piece of extra- 
ordinary good fortune, the temperatures of the soundings that 
we obtained were as curious as any we have obtained since ; and 
they suggested to me a general doctrine in regard to Oceanic 
Circulation, that all our subsequent researches have tended to 
confirm. The general facts of the case you will see by this 
map and the table by the side of it. Here is the north point of 
Scotland, the Orkney Islands, and Stornoway, the little port of 
the Hebrides from which we started. Here are the Faroe Islands. 
This dotted line is what is called the 44 hundred fathom line ” — 
that is, the line which bounds that curious platform, so to 
speak, of which the British Islands constitute the highest part. 
So that dotted line around the Faroe Islands represents water 
which is under 100 fathoms. Now between this and the 
Shetland Islands is a deep channel reaching down to 600 fathoms, 
which is a depth nearly equal to the height of Snowdon. 
Our soundings in the first expedition were made along this line, 
where we found, in a part of the channel, very low tempera- 
tures, such as 33, 32*2, and 32 degrees. But at the like depth 
in another part of this channel, the soundings, as marked in the 
upper part of the table, show a temperature of 45 to 48 degrees. 
Here was a very marked and curious contrast; for within a 
short distance of each other, in one instance only twenty miles 
apart, we found two very different climates at the same depth . 
Now the existence of these two very different climates showed 
itself, when we carefully worked it out afterwards, in two very 
distinct kinds of animal life, and in two very distinct kinds of 
deposit on the bottom of the ocean. I will first show how our 
next year’s work in the same region filled up and completed 
this inquiry, and gave us some very curious points in addition. 
You may imagine with what interest we went over this ground 
again, provided with our superior thermometers ; for the first 
year’s work was done with the old thermometers, only the 
