EQUIPMENT. 23 
a laboratory on shore at some point near deep water, carrying 
the bottles to the laboratory for analysis. 
A small chemical laboratory was fitted up on board the 
“Challenger,” where the elements of the chemistry and physics 
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1 
1 | 
Fig. 17.—Sigsbeo’s Fig. 18. — Section of Fig. 19.— Mode of Fig. 20.— Miller- 
Water-Cup. (Sigs- Sigsbee's Water-Cup. Attachment of Casella Thermom- 
bee.) (Sigsbee.) Thermometer and eter in Protecting 
Cups. (Sigsbee.) Case, with Sigs- 
bee’s. Attach- . 
ment. (Sigsbee.) 
of the water at the bottom of the oceans were worked out by 
Mr. Buchanan, the chemist of that expedition. From his an- 
alyses it appears that the amount of carbonic acid present in 
water taken from the bottom is much greater than in surface 
water, and that the amount of oxygen gas may be somewhat 
larger than at the surface. 
The apparatus used for bringing up the animals living at 
great depths is very simple. Until recently, the dredge first 
used by a Danish naturalist, O. F. Müller in the last century, 
