588 
ME. J. PEESTWICH ON SUBMAEINE TEMPEEATUEES. 
and ‘ Porcupine,’ culminating in that of the ‘ Challenger,’ has not only again directed 
attention to the subject of deep-sea temperatures, but has led to such improved methods 
of observation, that it may now seem late to bring forward the less accurate experi- 
ments of former observers. It might therefore seem almost a work of supererogation, 
now that the subject in connexion with these later voyages has been so ably and 
zealously taken up by my friend Dr. Carpenter, to introduce these more variable older 
elements into the discussion. Still the older observations, though restricted to com- 
paratively limited depths, have a wide range ; and in the case of the Arctic voyages 
they were obtained under conditions of so much difficulty and danger, that it may be 
long before similar experiments are repeated ; while many of the original opinions evi- 
dently deserve great consideration. It was, moreover, always my intention to complete 
the task I had begun when time and opportunity offered ; and as Dr. Carpenter’s work 
commences with the observations made by him on board the ‘Lightning’ in 1868, it 
may not be out of place to have a record of all that was done in temperature-soundings* 
up to that time, even as supplementary to the more exact work of later voyages. 
I may also notice that, notwithstanding the superiority of the more recent observa- 
tions and the inaccuracy of many of the older ones, there are a certain number of the 
latter which were made with great care, and which may vie with recent experiments in 
exactness ; while with respect to the others, the errors are such as may in most cases be 
computed and allowed for; or merely taking the old observations as they are, the 
comparative temperatures recorded at corresponding depths with the same or similar 
instruments have their own special value. The older observations are also so scattered 
through various narratives of voyages and in scientific periodicals, that no one can, 
without much difficulty of search, form an idea of their number and interest, or of the 
progress which the subject had made at the hands of the eminent men who had from 
time to time engaged in the inquiry on the Continent. I purpose, therefore, to show 
the state of the question at the time of the ‘ Lightning ’ expedition. For all that has 
been done since, I would refer to the exhaustive papers of Dr. Carpenter j\ 
In former voyages the temperatures are variously noted in degrees of Reaumur, 
* The few old observations of life at depths -will not now require notice. 
t “ Preliminary Report,” by Dr. "William B. Carpenter, Y.P.E.S., “ of Dredging Operations in the Seas to 
the North of the British Islands, carried on in Her Majesty’s Steam-vessel ‘Lightning,’ by Dr. Carpenter and 
Dr. Wyville Thomson, Professor of Natural History in Queen’s College, Belfast.” Proc. Eoy. Soc. vol. xvii. 
p. 168 ; Appendix, p. 197, 1868-69. 
“On the Bhizopodal Eauna of the Deep Sea,” by W. B. Carpenter, M.D., Y.P.E.S. Ibid. vol. xviii. p. 59. 
“ Preliminary Report of the Scientific Exploration of the Deep Sea in H.M. Surveying- vessel ‘ Porcupine,’ 
during the Summer of 1869, conducted by Dr. Carpenter, Y.P.R.S., Mr. J. Gwyn Jeffreys, E.R.S., and Prof. 
Wyville Thomson, LL.D., E.R.S.” Ibid. vol. xviii. p. 397. 
“ Report on Deep-sea Researches carried on during the Months of July, August, and September 1870, in 
H.M. Surveying-ship ‘Porcupine,’” by W. B. Carpenter, M.D., E.R.S., and J. Gwyn Jeffreys, E.R.S. Ibid. 
vol. xix. p. 146. 
“ Report on Scientific Researches carried on during the Months of August, September, and October, 1871, in 
H.M. Surveying-ship ‘ Shearwater,’ ” by William B. Carpenter, LL.D., M.D., E.R.S. Ibid. vol. xx. p. 535. 
