4 
CHAP. IL. J TENERIFFE TO SOMBRERO. 167 
We left Santa Cruz on the evening of Friday, the 14th of 
February. The weather was bright and pleasant, with a light 
breeze —force equal to about 5—from the north-east. Our 
course during the night lay nearly westward, and on the morn- 
ing of the 15th we sounded about 75 miles from Teneriffe and 
2620 miles from Sombrero Island, the nearest point in the Vir- 
gin Group, in 1891 fathoms, with a bottom of gray globigerina 
ooze mixed with a little volcanic detritus. The average of two 
Miller-Casella thermometers gave a bottom temperature of 2° C. 
The dredge was put over at 9 a. m., but came up empty some 
hours later, the rope having apparently fouled when paying 
out. 
The ship was steamed round to obtain the deviation of the 
compass, using the true bearing of the Peak of Teneriffe ; and 
this very important manceuvre may possibly have had some- 
thing to do on this occasion with the miscarriage of the dredg- 
ing, always a delicate operation at such depths when there is 
any drift. During the day Lieutenant Bethell took a series of 
temperatures, at intervals of 100 fathoms down to 1000 with 
Mr. Siemens’s resistance deep-sea temperature apparatus. A 
Miller-Casella thermometer was attached to the cable at every 
100 fathoms, so that the one method of determination might 
check the other. The sounding gave the following result : 
Temperature 
by Miller-Casella 
Depth Temperature by 
“Thermometer. 
Siemens’s Apparatus. 
Fathoms, 
100 1l}s3e33) (0) 16°°5 C. 
200 13 ‘6 Lar 
500 8-0 8 ‘0 
TOO 6 6 a 
800 bd sya 
1000 5 4. A:is 
This result appeared to be, on the whole, satisfactory for a first 
trial, and it was Mr. Bethell’s impression that with a little more 
