15 
Exrracrs rrom Lerrers to the author from the late Hon. George P. 
Marsh, Minister of the United states at Rome, and author of The 
Earth as Modified by Human Action :—‘1 am extremely obliged to you 
for a copy of your Réboisement in France, jst received by post. I hope 
the work may have a wide circulation. . . . Few things are more 
needed in the economy of our time than the judicious administration of 
the forest, and your very valuable writings cannot fail to excite a 
powerfal influence in the right direction. eee 
‘I have received your interesting letter of the 5th inst., with the 
valuable MSS. which accompanied it. I will make excerpts from the 
latter, and return it to you soon. I hope the very important facts you 
mention concerning the effect of plantations on the island of Ascension 
will be duly verified. 
. . . ‘I put very little faith in old meteorological observations, 
and, for that matter, not much in new. So much depends on local 
circumstances, on the position of instruments, &c.—on station, in short, 
that it is only on the principle of the tendency of some to balance each 
other that we can trust to the registers of observers not known to be 
trained to scientific accuracy. Even in observatories of repute, meteoro- 
logical instruments are seldom properly hung and guarded from dis- 
turbing causes. Beyond all, the observations on the absorption of heat 
and vapour at small distances from the ground show that thermometers 
are almost always hung too high to be of any value as indicating the 
temperature of the stratum of the atmosphere in which men live and 
plants grow, and in most tables, particularly old ones, we have no 
information as to whether the thermometer was hung five feet or fifty 
feet from the ground, or whether it was in any way protected from heat 
radiated from near objects.’ ~ 
Extract Lertsr from the late Professor Henry, of the Smithsonian 
Institution, Washington :—‘ The subject of Forest Culture and its in- 
fluence on rainfall is, just at this time, attracting much attention in the 
United States. At the last meeting of the American Association for the 
advancement of science a committee was appointed to memorialise Con- 
gress with reference to it. Several of the Western States Governments 
have enacted laws and offered premiums in regard to it. The United 
States Agricultural Department has collected statistics bearing on the 
question, and we have referred your letter to that establishment. 
‘The only contribution that the Smithsonian Institution has made to 
the subject is that of a series of rain-fall tables, comprising all the obser- 
vations that have been made in regard to the rainfail in the United 
States since the settlement of the country ; a copy of this we have sent 
to your address. 
“Tt may be proper to state that we have commenced a new epoch, 
and have, since the publication of the tables in question, distributed 
several hundred rain gauges in addition to those previously used, and to 
those which have been provided by the Government in connection with 
the signal service.’ etn : 
These notices and remarks are cited as indicative of the importance 
which is being attached to the subject discussed. 
