440 
NOTES TO THE 
Eotlischild, Editeiir, 13, Paie cles Saints Peres, Paris) — on the 
Anatomy and Physiology of Bees, by a Eussian engineer, Mr. 
Michael Girdwoyn. The drawings are marvellously beautiful. 
Every one interested in bees should have a copy of this work, 
which costs thirteen or fifteen francs. 
Effects of Trees on Kaixfall, p. 201.— Mr. Menzies, 
Deputy Surveyor of Windsor Forest, writes me thus : — 
"Mr. White has entered upon one of the most abstruse ques- 
tions of forest economy, to which much attention has been given 
since his time. The only time when trees do truly perspire is 
in the summer, when some kinds, such as notably the oak and 
beech, distil a sort of dew from their leaves. It is quite true also 
that they prevent evaporation from the surface of the ground, 
and so have a tendency to prolong the supply of water that any 
district may yield ; but on the other hand they themselves are 
great drinkers of the water in the subsoil, and so again they 
diminish the store. Whether these two tendencies counter- 
balance one another, or whether trees favour the storage of water 
most, has by no means been settled. Practically no one would 
think of surrounding a reservoir of pure drinking-water with 
trees ; because the falling foliage injures the water, and the 
effects of trees, in condensing water which is present in the 
air, are infinitesimal. Any account given by travellers of the 
diminishing of streams in any country in consequence of the 
denuding of the district of trees must be received with extreme 
caution — just as we know that we must be guarded in receiving 
from people of this country stories of the extremely cold winters 
and hot summers which used to prevail in tlieir youth. The 
statistics of rainfall have only been collected in England within 
the last ten years with anything like scientific accuracy, and in 
other parts of the world the science is quite unknown. Hence 
we have no real data to go upon, and without a series of actual 
gaugings of the streams extending over a number of years, a truly 
valuable opinion cannot be formed. Since Mr. White's time 
many thousands of acres in England have been cleared, and 
many thousands have been planted, but no data exist to form 
any reliable opinion as to the effect, if any, upon the rivers ; and 
such data would become vastly complicated, as it would be^ 
necessary at the same time to consider the effect of the agri- 
cultural drainage and the formation of canals, &c., that have 
been done since his time. My own opinion is that in England 
the trees have had no effect one way or the other. I have read 
many accounts of the effect, in other countries, of large forests in 
condensing the moisture on the hills, and the balance of evidence 
