TRANSACTIONS OF THE SECTIONS. 47 
been felt all along the line from Bombay to Simla; 35 inches of rain had also fallen 
in the first nineteen days of June, a quantity nearly equal to one-half of the average 
fall for the whole four and a half months of the monsoon. 
Meteorologists need a philosophic and comprehensive explanation of the causes of 
such atmospheric disturbances, which not only have an important bearing upon 
vegetable development, but unquestionably have a most disastrous effect upon the 
public health. At one period during the last quarter in London the excess of deaths 
exceeded by 200 daily or 1400 per week the usual average, and this mortality, 
chiefly from influenza, exceeding that from the Asiatic cholera, was attributable to 
atmospheric causes. 
T have thought it right to append the following rain-table as a valuable record. 
Register of the Pluviometer at Bombay from 1817 to 1847. 
June. 
Total fall 
July. 
August. 
September. 
October. 
Total fall in 
June, July, 
Years, Total fall | Total fall | Total fall | Total fall | Aug., Sept. 
in the in the in the in the inthe and October 
month. mouth, month, month. |. month. |in each year. 
inches. inches. inches. inches. inches, inches. 
1817 45°72 23°67 9:34 24°87 are b 
1818 22°54 17°€9 98°45 10°39 2:00 81:14 
1819 15:95 31:60 20:24 10:11 iis 77-96 
1820 18°82 28°37 19:49 10°66 vi 77°34 
1821 15:18 20°60 28-52 18:29 - 82-59 
1822 29:64 26°59 33°83 22:16 a 112-22 
1823 21-76 15:96 19-70 4-28 uss 61-70 
1824 3°89 8:07 17°86 1:78 2:27 33°97 
1825 24-45 25°17 12-94 9°68 Sas 72-24 
1826 17-75 26:97 8:40 23:50 1:87 78-49 
1827 49:15 10:29 10°51 10:16 0:92 81:03 
1828 23°58 52°75 17-22 22-08 6-40 121/98 
1829 27°86 19:78 -12-40 4:95 0°66 65:65 
1830 20-96 32°46 10°66 778 ais 71°86 
1831 22-16 27°31 | 27-64 22°34 2:08 101°83 
1832 13-63 48°05 4:65 711 0°65 74:09 
1833 12:50 21°80 13°35 23°54 0:20 71:39 
1834 14:16 21°83 18°05 12°55 3°88 70:47 
1835 9-99 4:27 35'76 12°17 0:42 62°61 
1836 21:36 24:05 37°41 4:69 ie 87:99 
18387 12-61 24:39 22-43 5°15 ad 64°58 
1838 29-70 8-70 734 5:04 is 50:78 
1839 18-28 32°19 18-45 4°70 ex 68°62 
1840 25-04 24:24 4:20 7:55 2-12 ~ 63°15 
1841 25:27 21-21 20:53 1:27 3°21 71-49 
1842 16°84 26°45 37°10 10-41 4:36 95-16 
1843 9°33 22°49 18-20 9:00 0:25 59:27 
1844 14:17 35:52 6:55 9:16 ao 65°40 
1845 19-70 20°44 6:56 8-03 tae 54:73 
1846 81-71 40°56 5°60 8-45 1:16 87-48 
35°47 16°80 8:92 5:80 0:32 67°31 
Average annual fall in the last 31 years ......) 75°42 
On the Compensation of Impressions moving over the Retina, as seen in 
Railway Travelling. By Sir Davip Brewster, KH, D.CL., PRS, 
§ V.P.R.S. Edin. 
At the Meeting of the Association at Cambridge I communicated to this Section 
the general fact of the existence of a neutral line, or a line of compensation, when 
‘the retina is submitted, in succession, to impressions moving with different veloci- 
ties and in the same direction. When we look, for example, at the lines into which 
‘the stones and gravel or other objects are drawn out by the velocity of the railway 
