138 TWENTIETH ANNUAL REPORT OF THE REGENTS. 



Table Y shows many facts and indicates conclusions : 



1. About ont -fifth more water falls in the second than in the first half year. 



2. Average depth of water to end of 1866, or for 30 years, is 32.559 inches. 



3. Greatest fall in a year, 1857, was -42.590 " 



The next. 1864, was 38.690, and 1850, 38.458, and 



in 1862 was 37.530 " 



The least fail in a year, 1858 24.356 " 



The next, 24.967 in 1851 ; 25.460 in 1838, and in 1844 26.200 " 



4. Greatest fall in a month, Sept. 1853 6.833 " 



The next 6.790 in Oct. 1846, and May 1864 6.540 " 



6.160 in July 1848, and Sept. 1841 6.140 " 



6.090 in Sept. 1861. 



The least fall in a month, Jan 1837 0.160 " 



The next Feb. 1841. 0.210, and then July 1854 0.252 " 



April 1837, 0.500, and then Oct. 1839 0.560 '' 



" Aug 1843, 0.700, and less than an inch more. 

 Between 1 and 2 inchi-s in 105 months; and in colder months, 

 2 and 3 " 101 " 

 '* 3 and 4 " 57 " 



4 and 5 " 34 " 



5 and 6 " 19 " 

 Above 6 " 6 " 



5. In the 30 years, September gave the most water. . . . 99.03, and av. 3.30 



■" next July, 97.06, and av. 332; and Oct. 96.64, and av. 3.22 



" May 92.27, and av. 3.07; and June 86.74, and av. 3.02 



" February gave the least water 59.57, and av. 2.00 



" Jan. 62.98, and av. 2.1; and March 64.00, and av. 2.10 



" April, 74.62, and av. 2.5 ; and Dec. 25.17, and av. 2.51 



SOME COMMON AND SPECIAL PHENOMENA. 



March 17 and 18. Flooding of a part of the city by the sudden melting 

 of the snow and attendant rain. 



1866, April 14. Some rain in the afternoon, and at sunset a splendid 

 rainbow, full half circle, with the two narrow and fainter bows below and 

 close to the primary bow. In these small lower bows, *iie colors are in 

 the same order as in the primary, the red being uppermost, orange and 

 yellow blended, and the green or faint blue the luwest and just perceptible. 



April 17. Aurora borealis rose over the north at 8-| p. M. ; brilliant 

 pillars or columns rose towards zenith; about 9 P. m, an arch rose from 

 the upper part of the luminous halo and extended from south-east to 

 north-west, thirty degrees, perhaps, north of the zenith ; at 9-| and a little 

 south of the place where the arch disappeared, were moving bands of 

 aurora, lying north and south parallel to the magnetic meridian, quite 

 across the canopy from north-west to south-east, first cloudy short masses, 

 then longer parallel bows, all moving towards the zenith, and disappeared 

 a little south of the zenith. 



The month has been warm and dry, and farming operations very easy 

 and pleasant. 



Sabbath, May 20. Highest temperature of the month, at 2 p* M., 80° ; 

 and at 4 P. m. a violent thunder shower began south and west, and extend- 

 ing north and moving eastward. Just after 4, lightning, rain and wind 

 were upon us, and soon hail in abundance, large stones, egg-shape, pear- 

 shape, oval or oblong, and with longer diameter two inches, globular, all 

 solid ice, or with snow in the centre or on one side of the centre, or some- 



