428 Obituary— Prof. Henry Carvill Lewis. 
we should expect that a moderate increase (beyond the mere four 
parts in 10,000 of our present atmosphere) of the food-stuff (carbonic 
acid) of plants would be favourable to more rapid production of 
vegetable tissue ; and on the same grounds we should equally expect 
that such an increase of the same gas, as to practically asphyxiate 
plants, would be fatal to them. But between the two limits there 
is ample room for Prof. Prestwich’s hypothesis, which is probably 
well founded. 
Why not experiment on the question? It is easy enough. 
Sachs (Lehrb. d. Botanik, p. 692) states that ‘experiments on 
plants (Vegetationsversuche) show that growth and the changes of 
material necessarily associated therewith only take place in the 
tissues (of plants) so long as free oxygen has access to them: in 
the absence of free oxygen (in einer saiierstofffreien Atmosphiire) no 
growth takes place; and if plants remain a longer time in such an 
atmosphere they die.” 
If, however, the percentage of carbonic acid in the present 
atmosphere were multiplied, say 100-fold, its volume would still be 
less than one-fifth that of the free oxygen present. This we should 
scarcely expect to reach the asphyxiation-proportion for plants. 
The above quotation is from the Leipzig edition (1874) of Sachs’ 
great work. It is probable that in the recent new edition much 
fuller information is to be found. 
WeLuincton CoLLecE, Berks. A. Irvine. 
4th May, 1888. 
(GESPEAR OWA EL Na 
PROF. HENRY CARVIEL (CEWIS,” MEAs iE iGuse 
Born NovemsBer 167TH, 1853; Dizp Jury 21st, 1888. 
Amonest the many and varied ties which serve to bind America 
and Iingland together in friendly union, there are probably none 
more sincere and reciprocal than those which subsist between the 
scientific men of the two countries. 
As Englishmen we take the warmest interest in the grand 
development of that wonderful country “on the other side,” and the 
hearty reception given to our American cousins here is returned 
with equal or even greater warmth by them, whenever we visit the 
New World. 
It is doubtless owing to their greater energy and enterprise that 
Americans are by far the more frequent visitors to our shores than 
are we to theirs. This is no doubt largely due to the historical 
attractions which an old country always offers to a new one, and 
also the desire to compare our scientific work and institutions with 
their own. 
No one amongst the many young scientific Americans of note has 
more earnestly cultivated English and European methods of research, 
or has worked with greater enthusiasm to carry his geological 
investigations from North America into Britain, than the subject of 
this brief memoir, Professor Carvill Lewis. H. C. Lewis was 
