200 TENTH ANNUAL REPORT OF 



previous. There is no animal that multiplies so fast as these, if the 

 sun be hot, and the soil in which the eggs are deposited be dry ; and 

 it is apprehended^ for these reasons, that these destructive insects 

 may reappear whenever the liot weather sets in early. 



July presented a most favorable specimen of our summer climate, 

 as if in compensation for the excessive solstitial heat of the preceding 

 month. There was scarcely a day in which the air was not refriger- 

 ated by southerly breezes. The barometer ranged persistently low, 

 and the atmospheric disturbance, indicated by its sinking to the mini- 

 mum on the 14th, was followed by accounts of showers of rain in va- 

 rious parts of the surrounding country from Yreka to San Francisco. 

 There was no rain at this point, but an increase of the humidity of 

 the atmosphere was manifested on several occasions by the formation 

 of clouds, and on the 18th vivid flashes of lightning were witnessed 

 in the eastern horizon. 



In August there predominated a comparatively large proportion of 

 the relative humidity of the atmosphere, accompanied by an almost 

 constant prevalence of southerly winds, and a persistently low range 

 of the barometer. These phenomena were followed in some parts of 

 the State by early rains. In Nevada, Sierra, Butte, and Plumsis, 

 heavy showers were reported to have iallen on the 19th. At the same 

 date it was cloudy here, and the relative moisture at the driest time 

 of the day amounted to 50 per cent, of saturation. 



In September the first rains of the season occurred antecedent to 

 the equinox. After the prevalence of a high wind for twelve hours, at- 

 tended with flitting clouds from the southwest, a nimbus passed over 

 the city about sunset on the 15th, dropping an almost imperceptible 

 sprinkle, and displaying a beautiful iris in the northeast. A heavy 

 bank of clouds was then seen to settle over the Sierra Nevada, occa- 

 sionally giving forth flashes of lightning. On the next evening, the 

 wind still prevailing from the same quarter, we were visited by a 

 shower sufficient to clear the atmosphere of dust for a short time. 

 Again on the following evening a heavy nimbus was seen to pass 

 from west-southwest to southeast, emitting vivid flashes of lightning, 

 followed by audible thunder. Prior to these occurrences the barom- 

 eter manifested considerable perturbation ; sinking to the minimum 

 on the 10th, and ranging generally low during the whole month. 

 During the latter part of the month was experienced somewhat of the 

 sultry, stagnant condition of the atmosphere which is peculiar to the 

 season when the wind is light from the northwest. 



October furnished further indications of the advent of the rainy 

 season. The relative moisture of the atmosphere had been for some 

 time gradually augmenting in per-centage, when, on the morning of 

 the 2yth, saturation manifested itself in the mist that prevailed until 

 10 a. m. The greatest degree of humidity previously observed was 

 on the 24th, the day of the eclipse of the moon, when the relative 

 moisture at the driest time of the day was 67 per cent., and the abso- 

 lute humidity 6.07 grains in each cubic foot. During the whole time 

 of the Ivmar obscuration the atmosphere was transparently clear, and 

 the phenomenon was seen perfectly through its progress ; the ther- 

 mometer ranging from*63° aty/i. 34?w. p. m.^ to 55° at Ih. 5m. a. m. ; 



