28 



POPULAR SCIENCE I^EWS. 



[Febuuaky, 1888. 



[Specially reported for the Popular Science .A^ewjs.] 



METEOROLOGY FOR DECEMBER, 1887, WITH 



REVIEW OF THE YEAR. 



TEMPERATCRK. 



The month began and closed with extremely 

 cold weather. The lowest observations were only 

 4° above zero, on the first, and 5° on the last, morn- 

 ings of the month. The 30th was the coldest 

 day, with an average of 8|° ; the first day averaged 

 11J°, and the last 14°. The 11th was 'the warm- 

 e.st day, with an average of 55|° and a range of 

 only 4°. The highest point was 58°, at the midday 

 observation. The preceding day and the follow- 

 ing were also unusually warm for the season, the 

 three days having an average of near 47°. The 

 entire month was li° above the average of the last 

 seventeen Decembers. The extreme Decembers 

 are given in the table above, with their wide range. 

 The temperature of the entire last year was a 

 near average of the last seventeen years, being 

 less than six-tenths of a degree below that average 



THE SKY. 



The face of the sky in 93 observations gave 38 

 fair, 9 cloudy, 32 overcast, 9 rainy, and 5 snowy, — 

 a percentage of only 40.9 fair. The average fair 

 the last seventeen Decembers has been 49. G, with 

 extremes of 40.9, in 1887, and 75.3, in 1877; show- 

 ing the present December to have been the least 

 fair in seventeen years. Full one-third of the 

 month was noted overcast, not including the rainy 

 or snowy days. The evening of the 11th, a warm 

 day, was foggy, followed by several clear, fine days. 

 A number of beautiful sunsets occurred during the 

 month, that on the 12th being unusually fine. 



PRECIPITATION. 



The amount of precipitation the past month, in- 

 cluding 5 inches of snow melted, was 4.38 inches; 

 while the average for the last nineteen Decembers 

 has been 3,87, with extremes of .73, in 1875, and 

 7.89, in 1884. The largest fall at one time was 1.55 

 inches, on the 28th. About 4 inches of snow fell 

 on the 26th and 27th, starting a few sleighs; but 

 on the following day snow fell, changing soon to 

 rain, with a strong east and south-east wind, which 

 swept away nearly all appearance of snow before 

 night. The amount of precipitation the past year, 

 including 68 inches of snow melted, has been 44.59 

 inches; while the average for the last nineteen years 

 has been 45.67, with extremes of 32.26, in 1883, 

 and 57.58, in 1878. 



PRESSURE. 



The average pressure the past month was 30.021 

 inches, with extremes of 29.10, on the 18th, and 

 30 80, on the 1st, — a range of 1.70, the highest 

 point reached by the barometer hi this locality lor 

 fifteen years. It was remarkably high in all the 

 north-eastern section of the United States, varying 

 from 30.70 to 31 inches at twenty of the thirty- four 

 stations of the signal service, — at AVashington, 

 30 80 ; Philadelphia, 30.82; Boston, 30.86; Albany 

 and Buffalo, 30.96; and at Oswego, 31 full inches 

 The average pressure of the last fourteen Decem- 

 bers has been 29.953, with extremes of 29.804, in 

 1876, and 30.073, in 1879. The sum of daily varia- 



tions the past month was 8.13 inches, giving anaver- 

 age daily movement of .262 inch. This average 

 in fourteen Decembers has been .259, with extremes 

 of .190 and .329. The largest daily movements 

 were .87, .73, and .57, all in connection with 

 storms. The first third of the month was of uni- 

 formly high pressure. 



WINDS. 



The direction of the wind in 93 observations 

 gave 19 N., 1 S., 6 E , 19 W, 8 N.E., 6 S E., and 

 7 S.VV., — an excess of 40 northerly and 33 west- 

 erly over the southerly and easterly, and indicat- 

 ing the average direction of the month to have 

 been W. 50° 29' N. The westerly winds in the last 

 eighteen Decembers have uniformly prevailed over 

 the easterly by an average of 54.44 observations, 

 and the northerly over the southerly, with two 

 exceptions, by an average of 18.50; indicating the 

 approximate general average for December to be 

 VV. 18° 49' N. The longitudinal extremes have been 

 33 W. and 76 W.,-— a range of 43; and the latitu- 

 dinal 40 N. and 9 S. , — a range of 49. The relative 

 progressive distance travelled by the wind the past 

 month was 51 86 units, and during the last eigh- 

 teen Decembers 1,035 such units, — an average of 

 57.50 ; showing more opposite winds the past 

 month than usual. The wind in connection with 

 the storm on the 28th became very violent for a 

 short time toward the close of the day. 



The above table of comparisons is very compre- 

 hensive, showing at a single view the meteorology 

 of the last year, compared, month by month, with 

 that of a series of years, in each of the five depart- 

 ments of observation. The table chiefly explains 

 itself. I may notice, however, under the head of 



Temperature, the first column, how peculiarly the 

 scale rises from January, the coldest month, to 

 July, the warmest, and then declines by very nearly 

 corresponding degrees to January; the most rapid 

 changes occurring just after the equinoxes, and the 

 least rapidly just after the solstices. The year 

 1887 was a near average, as a whole, and yet sev- 

 eral months differed widely from their appropriate 

 average, as .May, July, and September. The finst 

 column under 



Percenlaye fair, shows that our most cloudy 

 months in seventeen years have been December, 

 March, and .\pril. There is also apparent a regu- 

 lar increase and decrease through most of the year, 

 but especially in the warmer months. l!y longer 

 observation a more regular scale may be found to 

 exist through the year, or with certain exceptions. 

 The sun is a mighty ruler of the clouds as well as 

 heat. The year 1887 was peculiarly cloudy, espe- 

 cially July, which, instead of being one of the 

 brightest months, came near being most cloud}' of 

 all. 



The rauifull is scarcely less valuable than the 

 heat of the sun, and is caused by it; yet our hottest 

 months are not the most rainy. ^larch stands at 

 the head, with February and January closely fol- 

 lowing, while June and September are at the other 

 extreme. The year 1887 was an inch below the 

 average, the winter months being largely in excess, 

 leaving most of the warm season quite deficient. 



The TJre.sswre, observed at the morning and even- 

 ing hours only, is constantly varying, and yet under 

 laws as exact as gravitation itself, with modifying 

 influences. September and October maintain the 

 highest pressure, March and April the lowest. 

 The year 1887 was above the average, five months 

 exceeding an average of 30 inches. The highest 

 point reached in fifteen years was 30.80 inches, in 

 December, 1887, and the lowest was 28 70, in No- 

 vember, 1873, — a range of 2.10 inches, indicating 

 a difference of more than one pound to the scjuare 

 inch. 



The xoinds are among the most fickle of all things ; 

 and yet these, too, have laws, which become mani- 

 fest by careful study. After eighteen years' obser- 

 vation three times daily, a degree of order is 

 noticed, even in the winds. Beginning with Sep- 

 tember, we find the average of that month to be 

 due west. October follows with an inclination 

 W. Iu° 56' N., and so on to April, a constant 

 northerly increase for seven months ; then a sudden 

 decrease in May, 28° le.ss northerly, followed by 

 other warm months with a strong soulherlij inclina- 

 tion. In examining the winds of 1887 we find 

 wide contra.sts, especially with May and August, 

 each largely reversing its usual order. Septeml)er, 

 October, and December were largely north, causing 

 the entire year to be 14° 12' more northerly than 

 usual. The yearly excess of the northerly over 

 the southerly winds in eighteen years has been 80^, 

 while that of the year 1887 was 212. With such 

 extremes and fickleness, we need longer observation 

 to .secure even an approximate average with satis- 

 faction. . D. W. 

 Natick, Jan.. 6, 1888. 



[Sinxially reported for the PojAilar. ScUnce Ntwi from the 

 Observatory of the College of Xew Jersey.] 



ASTRONOMICAL PHENOMENA FOR 

 FEBRUARY, 1888. 



TiiKUE will be an eclipse of the Sun on Feb. 11, 

 invi.sible in the United States. The only accessible 



