SECRETARY'S REPORT. 43 



much suffering from this cause; for, from 1779 to 1787, there 

 was a succession of favorable seasons, and the various crops 

 were remarkably abundant. 



In the course of our examination, we arc led to the conclu- 

 sion, that a small amount of rain, evenly distributed over the 

 season, will afford sufficient moisture for the support of vege- 

 tation ; while, had the same amount fallen in a single shower, it 

 would have done comparatively little good. Thus, in 1791, 

 2.30 inches of rain fell in April, 2.55 inches in May, 2.G9 inches 

 in June, and but 1.79 inches in July.-" These amounts are be- 

 low the average of those months, and would have led to a severe 

 drought in July had not the distribution been very general over 

 the month. To show the distribution of rain in July, for in- 

 stance, when the smallest quantity fell, it may be stated, that it 

 rained on the 30th of June, on the 8th, 12th, 14th, 16th, 17th, 

 20th, 21st, 22d, and 24th of July; though, as will be seen from 

 the amount given above, no great quantity of rain could have 

 fallen at any time. And again, in 1792, the rains for July were 

 but 1.60 inches, and for August but 1.34 inches, but the distri- 

 bution over these months was as follows : In July, it rained on 

 the 9th, 10th, 16th, 17th, 21st, 24th, and 30th; and in August, 

 on the 6th, 12th, 13th, 14th, 24th, 25th, 28th, and 30th; and 

 we find, accordingly, no notice of any great difficulty from want 

 of rain in that year. But had the same amount fallen on one 

 day. and the other thirty days been clear, it is easy to see that 

 vegetation must have suffered severely. 



Soils, it is true, differ greatly in character, and some are far 

 more liable to suffer from drought than others ; but all soils 

 depend more or less upon the amount of rain which falls, and 

 its distribution over the seasons, for their fertility. The 

 amount required differs of course with the nature of each soil, 

 the temperature of the atmosphere, and its power to promote 

 evaporation from the surface, and upon many other circum- 

 stances, which make all accurate investigations difficult and 

 complicated. 



The earth, with our climate, should retain at least three- 

 hundredths of an inch of water to every inch in depth during 



* As appears by a record kept by Dr. Prince, of Salem, which is now deposited 

 in the library of the Essex Institute. 



