5 
for every 8o0 fathoms depth, and the error at that depth was about 
4° Fah. Several experiments were made on the subject in the spring 
of 1869, in the course of which Dr. W. A. Miller, the treasurer 
of the Koyal Society, suggested a very simple plan by which 
this error was obviated. The ordinary bulb of the thermometer was 
surrounded by a second, and the intervening space nearly, but not 
completely, filled with spirits of wine, the vapour of that liquor occupying 
the remainder of the space. The pressure only acted upon the outer bulb, 
and was not transmitted to the inner in any perceptible degree. These 
instruments were tested by being exposed in a strong vessel filled with 
water to great pressure, (three tons to the square inch,) in an hydraulic 
press, before being used at sea. They took longer to indicate, but that 
was unimportant. A full description of this instrument, and of the pre- 
liminary experiments connected with it, will be found in the Proceedings 
of the Royal Society for June 17th, 1869. In the course of a long series 
of comparative experiments made at sea, these instruments were found 
to work perfectly, while no other form of thermometer which was tried 
gave satisfactory results. 
The apparatus for obtaining samples of water at various depths con- 
sisted simply of a cylindrical brass tube, furnished at each end with an 
accurately ground valve, opening upwards. The tube was tied to the 
sounding line, and as long as it was descending water passed freely through 
it, but as soon as the motion was reversed, the pressure of the water above 
kept the valves closed, and the water that entered the bottle at the lowest 
point of its descent was retained there, and brought up for examination. 
As long as the bottle, or tube, was kept nearly vertical, it answered its 
purpose admirably. The water thus obtained was examined without delay 
for (1) the nature and quantity of the gases dissolved in it, (2) the organic 
matter in it, and (3) its specific gravity, and some samples were preserved 
for a more complete chemical investigation on shore. 
It will now be desirable to give some account of the results obtained. 
The greatest depth at which the dredge was worked was 2,435 fathoms, 
14,610 feet below the surface of the sea, a depth nearly equal to the height 
of Mont Blanc above it. At this, and at every lesser depth, living animals 
were found, representatives of almost every type of marine Invertebrata, 
many of them possessed of eyes and colour, rendering the inference that 
light penetrated to these profound depths almost unavoidable. Many of 
the creatures discovered were altogether new, and others were hitherto 
only known as fossils. In the Mollusca alone the dredging results added 
