IS 



Extracts from Letters to the author from the late Hon. George P. 

 Marsh, Minister of the United States at Eome, and author of The 

 Earth as Modified by Human Action : — ' I am extremely obliged to you 

 for a copy of your Riboisement in France, just 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 

 powerful influence in the right direction. . . . 



'I have received your interesting letter of the 5th inst., with the 

 valuable MS8. 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 Letter 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. 



' Ttie 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 rainfall in the United 

 States since the settlement of the country ; a copy of this we have sent 

 to your address. > 



' It 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.' 



These notices and remarks are cited as indicative of the importance 

 which is being attached t6 the subject discussed. 



