CHAP. II.] THE CRUISE OF THE ‘ LIGHTNING, 79 
The general results of the ‘ Lightning’ expedition 
were upon the whole as satisfactory as we had ven- 
tured to anticipate. The vessel was certainly not well 
suited for the purpose, and the weather throughout 
the cruise was very severe. During the six weeks 
which elapsed between our departure from Oban and 
our return only ten days were available for dredging 
in the open sea, and on four of these only we were in 
water over 500 fathoms deep. On our return Dr. 
Carpenter submitted to the Royal Society a pre- 
liminary report on the general results of the cruise, 
and these were regarded by the Council of the Society 
as sufficiently new and valuable to justify a strong 
representation to the Admiralty urging the importance 
of continuing an investigation which had already, 
even under unfavourable circumstances, achieved a 
fair measure of success. 
It_had_ been shown beyond question that animal 
life is varied and abundant, represented by all the 
invertebrate groups, at_depths in the ocean down to 
650 fathoms at least, notwithstanding the extra- 
ordinary conditions to which animals are there 
exposed. 
It had been determined that, instead of the water 
of the sea beyond a certain depth varying according 
to latitude having a uniform temperature of 4° C., an 
indraught of Arctic water may have at any depth 
beyond the influence of the direct rays of the sun a 
temperature so low as — 2°C.; or on the other hand, 
a@ warm current may have at any moderate depth a 
temperature of 6°5C.: and it had been shown that 
great masses of water at different temperatures are 
moving about, each in its particular course ; main- 
