46 The Ottawa Naturalist. [May 



clouds and winds, or absorbed in the evaporation of rain. The 

 averag-e minimum temperature^ of every ten days of May and 

 June, 1903. were respectively 37.8*^, 51.8^, 51. i*"^, 52.6", 51-8*' 

 and 533''; while the corresponding maximum temperatures were 

 67.7*=', 81. i", 70 8°, 80.5°, 67.8'' and 71.1^. It was in May that 

 the most rapid rise in minimum temperature took place, namely 

 that from about 40*^ to about 50*^ during the middle of May, 1903, 

 and the latter part of May, 1902. 



Comparing now the rainfall of the two seasons, .ve find that 

 there is a marked difference in the amount and still more in the 

 distribution of precipitation. It 1902 it amounted during the four 

 months under consideration to 12.32 in.; in 1903 to 8.97 in. Or, 

 leaving- out of account the last third of June, which my plant- 

 observations do not cover, 10.65 '"• ^'^"^ 5.06 in.; that is more 

 than twice as much rain in 1902 as in 1903 for the period covered 

 by my observations. In 1902 the rain was well distributed, being 

 for March, April, May and the first two thirds of June 3.47, 2.74, 

 1.82 and 2.62 inches respectively, which is not very different from 

 the average for 20 years. But in 1903 the figures are 1.35, .95, 

 . 12 and 2.64 inches. In >go3, therefore, there was comparatively 

 little precipitation in the spring before June, and next to none in 

 May ; and even in June the rain did not fall in any appreciable 

 amount until the 12th, when it rained 1.59 inches and continued 

 rainy throughout the rest of the month. Furthermore, there was 

 no rain in April after the 7th. In fact from the 8th April to the 

 iith June inclusive there fell only .22 in. of rain ! That period, 

 therefore, of over two months' duration, was literally one long- 

 drouth. Occurring- as it did, however, so early in the year, when 

 the ground was saturated with the winter snows, its effect was, 

 as we have seen, to force vegetation forward rather than to retard 

 it, until towards the end of the drouth. For we found that, in spite 

 of the fact that the weather continued warmer, and indeed in- 

 creasingly warmer in the first part of June, 1903, as compared 

 with 1902, yet there was an actual falling off in the lead of 1903 

 over 1902 in plant-growth during that period, when the average 

 daijy temperature was 7^ higher in 1903. 



I was not surprised at this result, as I remember noticing the 

 blighting- effect of the drouth on certain of our wild plants. I 



