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ten units of caloric per minute. Such a quantity of heat would make a litre of water at freezing-point boil in ten minutes, and is equivalent to the theoretical action of a one horse-power. He further states that he had proved the possibility of keeping hot-air machines going by means of solar rays, and had succeeded in making a few litres of water boil by exposure to the same agent ; and in June, 1866, he had made a small steam-engine work by converting water into vapor with the assistance of a reflector one mètre square.
THE COLORS OF FOLIAGE.
The green color of leaves, one element of which must be a vegetable blue, has led an American experimentalist to the conclusion that leaves turn red at the end of the season through the action of an acid, and that the green color could be restored by the action of an alkali. The conclusion has been verified, the Athenæum declares, by experiment. Autumnal leaves placed under a receiver with vapor of ammonia in nearly every instance lost the red color and renewed their green. In some, such as sassafras, blackberry, and maple, the change was rapid, and could be watched by the eye, while others, particularly certain oaks, turned gradually brown, without showing any appearance of green. — Canadian Naturalist.
ON THE GREAT SNOW FALLS OF 1869.
BY C. SMALLWOOD, M.D., LL.D., D.C.L. The more than usual amount of snow which fell during the winter 1868-9, renders it worthy of record for comparison with past and future observations.
The first snow of the winter (1898-9) fell on the 17th day of Octo. ber, and though inappreciable in quantity, ushered in a season of very heavy snow falls.
The total amount which fell during the month of October was.
4.92 inches During the month of November.
.17.28 During the month of December.
.27.96 During the month of January, 1869.
.28.07 During the month of February.
73.76 Up to the 15th March....
The mean average depth of the snow fall for the past twenty years was 79.50 inches per annum.
The greatest depth which fell in one month during the above period fell in January, 1861, and was 31.80 inches.
The total depth which fell in 1861 (a year of great snow fall) was 99.58 inches.
Last year (1868) 105.27 inches of snow fell ; this is above the year. ly average, but is owing in a great measure to the unusual large amount which fell in November and December.
The first heavy fall commenced at 7 a. m. on the 3rd of February and ceased at 4 p. m. on the 4th day, 25,44 inches having fallen. The barometer fell from 29.751 inches to 28:841 (a range of 0.910 inches). The mean temperature of the 3rd day was 17 degrees, and of the 4th day 21 degrees ; wind was from the N. E. by E. ; greatest mean velocity 18.42 miles per hour.
The second heavy fall commenced at 3.15 p. m. on the 14th day, and ceased at 2.15 p. m. of the 15th ; there fell 14.90 inches. The barometer stood at the commencement at 30.001 inches and fell to 29.175 (a range of 0.826 inches); the wind was from the N. E. by E.; greatest mean velocity 19.11 miles per hour. The mean temperature of the 15th day was 19 degrees.
A third fall, which was remarkable for heavy drifts and somewhat severe cold, commenced at 4 a. m. on the roth of March and ended at II p. m., during which time there sell 8.82 inches. The barometer attained the lowest reading at 10 p. m., and indicated 29.119 inches ; wind was from the N. E. by E., and was succeeded by a heavy gale from the West. The mean temperature of the day was 12. 1 degrees ; the thermometer at 7 a. m. stood at 16°.1 and fell to 8o.o at 2 p. m., and at 9 p. m. it rose to 12o.2.
The heaviest fall of snow on record to which we have had access, occurred on the 17th and 18th of January, 1827, when from 60 to 70 inches of snow fell. Drifts of from 12 to 15 feet high were common in many places.
February has not generally been characterized by very heavy snow falls, being for the most part dry and cold. The heavy fall of November last far exceeds the usual average for that month, which is about 6 inches. December, 1830, 1831 and 1834 showed a fall of 26.50 inches, 27.45 inches, and 27.70 inches respectively ; large amounts fell in February, 1831, viz., 23.30 inches; in 1832, 25.85 inches ; and in 1835, 21.80 inches, but these are exceptions; and March, 1832, shows an
amount of 21.35 for that month. The amount of snow which fell in the month of December corresponds very closely to the above amounts.
We may state, for the purpose of illustrating our climatology, that from the year 1824 up to 1868, a period of 44 years, the ice left the River St. Lawrence in front of this city-varying from the earliest period, 16th March (1825), to the latest, April 28 (1855), showing a variation of 43 days during this period of 44 years, but these early periods are not confined to late dates, but occurred in March, 1825, 1828, 1834 and 1842; the intervening years vary from 3rd to the 28th of April inclusive.-Canadian Naturalist, March, 1869.
THE WIND AND THE WEATHER.
Aristotle, in his treatise styled “Politics," says that there are, properly speaking, only two forms of political constitutions—those which are free, and those which are not frec. In the same way it is said of the winds that there are really only two winds, n umely, northerly and southerly, because all other winds are merely occasional deviations from these two directions.
Most winds are liars, as they do not come from the regions from which they appear to flow. The ENE., the NE., and the NNE, are much more truly northerly winds than the N. itself, and in the same way the WSW., the SW., and the SSW, much more truly southerly than the S. itself.
The regular shisting of the wind in the northern hemisphere is as follows-forwards, or rather in circuit :
>-> S., SW., W., NW., N., NE., E., SE., S. >-> Such is the circuit, and the writer in the Book of Ecclesiastes (chap. i. ver. 6) would seem to indicate the law of gyration as explained by Dove : “ The sun also ariseth, and the sun goeth down and hasteth to his place where he arose. The wind goeth toward the south, and turneth about the north ; it whirleth about continually, and the wind returneth again according to his circuits." But indeed the ancients had generally observed the fact. In the southern hemisphere the shifting of the wind is as follows :
>-> S., SE., E., NE., N., NW., W., SW., S. >-> That is to say, still with the sun ; and the entire ordination is accurately expressed by the old sailors' saying
cWhen the wind veers against the sun,
Trust it not for back 't will run."
Since, therefore, the regular rotation of the wind is universal, it must be independent of the relative position of the oceans and continents, and also independent of the mean direction of the wind and its annual variations.
The effect on the consequent variations of the meteorological instruments, changes at the different seasons. The coldest point of the compass in Europe is nearer the NE. in winter, and nearer the NW. in summer ; and, accordingly, the warmest point in winter is nearer SW., and nearer SE. in summer.
In the Northern Hemisphere-1. The barometer falls with F., SE., and S. Winds ; with a S.W. wind it ceases to fall and begins to rise ; it rises with W., N.W., and N. Winds; and with a N.E. wind it ceases to rise and begins to fall. 2. The thermometer rises with E., SE., and S. winds; with a SW. wind it ceases to rise and begins to fall ; it falls with W., NW., and N. winds; and with a NE. wind it ceases to fall and begins to rise.
In the Southern Hemisphere-1. The barometer falls with E., NE., and N. winds ; with a NW. wind it ceases to fall and begins to rise ; it rises with W., SW. and S. winds; and with a SE. wind it ceases to rise and begins to fall. 2. The thermometer rises with E., NE., and N. winds ; with a NW. wind it ceases to rise and begins to fall; it falls with W., SW., and S. winds; and with a SE. wind it ceases to fall and begins to rise.—Manual of Weathercasts.
That correct forecasts of the weather are of commercial value, it is not difficult to perceive, especially as regards certain lines of business, which are directly affected by the character of the seasons.
It is an mportant matter, for instance, for a manufacturer of cutters or sleighs, or a manufacturer of skates, to have a general idea of an approaching winter, to know, for instance, whether or not it will be an open season or if the snow-fall will be heavy. Furriers, clothiers, ice-dealers and many other business men are interested to a greater or less extent, and, in this connection, a perusal of Mr. Vennor's correspondence is in. structive. Among the letters received by him we find one from a Buffalo Ice Company, requesting him to inform them concerning the weather for the next forty-five days from the date in that neighborhood. The proprietors of a leading New York place of amusement
send Mr. Vennor an addressed envelope and stamps, requesting a forecast of the probable weather during a certain week.
A prominent auctioneer, also of New York City, holds an open air auction in a country part on a certain date, but will change it to another date if Mr. Vennor advises.
An old soldiers' parade being on the tapis, the originator writes to Mr. Vennor to fix the day. The letters from New York and Boston are the most numerous, and are principally from ice companies. Other communications have been received from Greenville, Illinois ; Fort Wayne, Indiana ; Jerusalem, N.Y.; Northampton, Mass. ; Rich
; mond, Pa. ; Hudson, N.Y.; Reading, Pa. ; Toronto, Ont. ; Cleve. land, O., &c., &c., all pertaining to the weather to come.
A Louisville, Kentucky, correspondent mentions the fulfilment of one of Mr. Vennor's forecasts, and asks for an 1880 Almanac, stating that “people now go entirely by your predictions."
SIGNS OF FOUL WEATHER.
BY DR. JENNER.
The hollow winds begin to blow;
* The line,“ Hark how the chairs and tables orack," do incorrect; as the cracking. that is, contraction, indicates, tair weather, from the dimination of moisture. teinmetz.