68 
Lords Commissioners of the Admiralty wrote on the 14th July that 
they had given orders for Her Majesty’s steam vessel “ Lightning ” 
to be prepared immediately at Pembroke to meet the wishes of the 
Royal Society. The “ Lightning ” left Pembroke on the 4th 
August 1868. Drs Carpenter and Thomson, and Dr Carpenter’s 
son Herbert, joined the vessel at Oban, whence they sailed on the 
8th August. They reached Stornoway on the 9th, and left it for 
the north on the 11th. On the same afternoon they dredged in 60 
to 100 fathoms ; on the 13th in 450 fathoms, finding no bottom, 
but the high temperature of 9 ‘5° C.; afterwards in 600 to 700 
fathoms in the same locality. Bad weather frequently impeded the 
dredging operations. On the return of the vessel to Stornoway on 
the 9th September, Dr Wyville Thomson was obliged to leave her 
to attend to duties in Dublin, but Dr Carpenter remained with the 
vessel, left Stornoway again on the 14th September and dredged in 
650 fathoms, but on the 21st the weather was so bad that the work 
had to be concluded. There were only ten days available for 
dredging in the whole six weeks, and on only four of these was the 
vessel in water over 500 fathoms deep. Yet a fair measure of 
success had been achieved. 
It was shown that varied and abundant animal life, represented 
by all the invertebrate groups, occurs at depths in the ocean down to 
650 fathoms at least ; and that, instead of deep sea water having an 
invariable temperature of 4° C., great masses of water, at tempera- 
tures varying from 2° C. to 6*5° C., maintain a remarkable system of 
oceanic circulation, and yet keep so distinct from each other that 
both may be found within the limit of an hour’s sail. It was also 
ascertained that a large proportion of the forms living at great 
depths of the sea are of unknown species, and identical with tertiary 
fossils previously believed to be extinct. 
The next year, 1869, saw Wyville Thomson again engaged in the 
examination of the physical, chemical, and biological conditions of 
the ocean depths, for the Lords Commissioners of the Admiralty 
had acceded to the additional request of the council of the Royal 
Society and had set apart the “ Porcupine,” a small vessel fitted up 
for surveying purposes and admirably adapted for the continuance 
of these researches, from the beginning of May to the middle of 
September. As it was impossible for those connected with the 
