THE CANADIAN JOURNAL No. XXXVIII.-MARCH, 1862. NEW SERIES. MEAN METEOROLOGICAL RESULTS AT TORONTO, FOR THE YEAR 1861. BY G. T. KINGSTON, M.A., DIRECTOR OF THE MAGNETICAL OBSERVATORY, TORONTO. Read before the Canadian Institute, February 22nd, 1862. THE year 1861, with respect to its temperature, exhibited, as a whole, nothing extraordinary, the mean of the year differing from the average of twenty-two years to the extent of only 0°.10 in excess. The monthly means, moreover, did not differ in a marked degree from the means proper to the several months derived from twenty-two years, the average deviation, without regard to sign, being 2°.24; while the average deviation in the whole period of twenty-two years, and referred to the same standard, was 2°.44. If, however, the signs of the deviations be taken into account, it will be seen that the compensations by which the annual mean was maintained, were of the kind that may be styled unseasonable, being such as tended to weaken rather than to intensify the distinctive characters of the different parts of the year. Thus, from May to August-comprising the greater part of the year in which the temperature is above the yearly mean the monthly means were relatively low; while in February VOL. VII. G and December, the monthly means were relatively high. The depression (3°.9) in the temperature of May, was never exceeded in any May of former years, and was nearly approached only in 1849 and 1851, when in both cases the cold of May was succeeded by unusual warmth in June and July. The abnormal warmth of April served only to aggravate the evil, by hastening the vegetation that was thrown back by the frosts that followed in May. The bad effects of a generally low summer temperature may perhaps be modified, as regards some plants, by occasional bursts of heat, though they be necessarily balanced by unusually low temperatures at other parts of the season. No such mitigating circumstances occurred in 1861, as the warmest day and the absolutely highest temperature of the year were both considerably below the twenty-two years' average of these quantities. The hygrometric condition of the summer was not favourable; the mean relative humidity of May, June, and July, being 70 against 74, the twenty-one years' average for these months. But as the temperatures were low, the foregoing numbers do not present so strong a contrast as do the tensions of vapour, which for the same three months were 359 in 1861, and 393 on the average of twenty-one years. The contrast in this respect between 1860 and 1861, was very conspicuous in May, the tension of vapour for this month being more than 41 per cent. greater in 1860 than in 1861. May and June were 8 per cent. and 16 per cent. less cloudy than is usual in those months; while later in the season, when a bright sun is more in request, clouds were more than 20 per cent. in excess. The depth of rain, which on the whole year was three inches in defect was deficient in June and July to the extent of more than an inch and a half. In May, when rain is an hindrance to gardening and agricultural operations, it was rather in excess; while, as before stated, there was a want of that moisture in the air whose presence is favourable to the development of young leaves. In the following summary, the chief meteorological elements relative to the year 1861, are compared with the average results derived from a series of years, as well as with extreme values that have occurred during the same series: 46°.36 42°.16 (in 1846) (in 1856.) August. July. July 1854 Aug 1860 when the mean temp. of the month was 65°.48 66°.85 Coldest month.... when the mean temp. of the month was Difference between the warmest and coldest months Mean of deviations of monthly means,' from their respective averages of 22 years, signs of deviation being disregarded.. 72.47 64°.46 January. February Jan. 1857 Feb. 1848 19.86 22°.98 12°.75 45°.62 43.87 26°.60 29.24 20.44 { Month of greatest deviation without re- Decem'r. January. Jan. 1857 gard to sign.... when the monthly mean differed from the 22 years' average of the same month by Warmest day There were twenty-seven days when the mean temperature of the day differed 12° and upwards from the normal mean of the day. Their distribution among the several months may be seen in the following table: * The mean temperature of the warmest day in the foregoing table, refers to the twentytwo years average of the warmest days in each year, irrespective of their dates, the average date being simply the arithmetic mean of the several dates measured from any fixed epoch. The same remark applies to the coldest day, and to the maxima and minima of the year. As regards the low temperatures, the averages are derived from the coldest days and lowest temperatures in successive winters,--December being considered to belong to the following year. There were one hundred and three days when the mean pressure of the day differed 0.200 of an inch and upwards, from the adopted normal mean of the day. Their distribution through the year may No. of days on which rain fell.. 136 fell in when it amounted to in 1856 136 in 1861 80 in 1841 Greatest depth in one month November September Sept., 1843 Sept. 1848 17 June Nov. 2nd Oct. 6, 1849 Greatest depth of rain on one day which fell on Greatest depth in one hour 30.324 S 43.555 $21.505 in 1843 106 Aug. 21st The average minimum of cloudiness in the second column, is the minimum of the twelve monthly means of nine years, and does not always include the lowest months of each year, as these fall differently in different years. This explains why the highest minimum in the fourth column should be numerically equal to the minimum on the average of nine years. |