160 EFFECTS OF FORESTS ON RAINFALL. 



the mean annual quantity of rain." The deliverance of Becquerel is 

 in accordance with this. He says : " Great clearings diminish the 

 quantity of spring water in a country." But he says, " It has not 

 been ascertained whether this effect should be ascribed to a less 

 quantity of rain which falls annually, or to a greater evaporation 

 from the soil of rain watei", or to a new distribution of showers of 

 rain." 



The opinions thus expressed are based on observations of facts. 

 But along with these facts there are other facts which have already 

 been referred to, and which require to be taken into consideration, 

 if we would learn the whole truth on the whole of the subject. It 

 has been stated that in the annual report of the Director of the 

 Meteorological Observatury in the Central Pa^^k of New York, for 

 1871, Mr Draper addresses himself to the question — Does the clear- 

 ing of laud increase or diminsh the fall of rain 1 and in a preceding 

 chapter I have given his answer. 



He gives summaries of observations made in each year, and in 

 each quarter of the years 1869, 70, 71 ; he states that the indica- 

 tions given by the instruments of the observations under his direc- 

 tion may he thoroughly relied on, and he concludes, " so far as these 

 years are concerned there does not appear any evidence of a decrease, 

 on the contrary, in the last, there is a very considerable excess on 

 either of the others." 



Citing, then, observations made in England since 1677, and in 

 unbroken continuance since 1725, in Scotland since 17-31, in Ireland 

 since 1791, he shows that where a lengthened period and an 

 extensive area are embraced by the observation, there is a perfect 

 compensation, the decrease at one place being compensated by the 

 increase at another, and that even in the same locaUty this principle 

 of compensation might be seen. 



When these facts are taken into consideration along with the 

 other facts which have been cited, the two classes of facts may at 

 first appear to the inconsiderate to be inconsistent and incompatible 

 with each other ; but if all be facts they must be compatible and 

 consistent, and a little consideration may suffice to show that they 

 are so. 



Harland Coultas, in a work entitled "What may be learned from a 

 Tree," published in New York in 1860, in a passage cited by Marsh 

 says, " The ocean, winds, and woods, may be regarded as the several 

 parts of a great distillatory apparatus. The sea is the boiler, in 



