88 THE DEPTHS OF THE SEA. [ CHAP, III. 
chyurous crustacean which had not previously been 
taken in the British seas, 
Here the Miller-Casella thermometers were tried 
for the first time and compared with those of the 
ordinary construction. The minimum recorded by 
one of the former was 5°2 C., while that recorded by 
one of the best ordinary instruments of the Hydro- 
graphic Office pattern was 7°3 CAs this difference 
of 2° C. was almost exactly what the results of the ex- 
periment previously made had indicated as the effect 
Fig. 9.—Geryon tridens, KRoyER. Young. Twice the natural size. (No. 7.) 
of a pressure of 1 ton on the square inch, which is 
about equal to the pressure of a column of sea-water 
of 800 fathoms, this close coincidence gave great 
confidence in the practical working of the protected 
instrument, a confidence which all subsequent ex- 
perience has fully justified. 
Mr. Gwyn Jeffreys and his companions next pro- 
posed to examine the sea-bed between Galway and 
Porcupine Bank, a shoal discovered during one of 
