METEOROLOGY. 



491 



of the Carnatic rainfall was not representative 

 of a similar variation in that of Southern India 

 generally. A lack of exact correspondence 

 further appeared in the review of the preva- 

 lence of droughts and dearths. But while the 

 theory is not sustained, Mr. Blanford would 

 still not "hastily conclude from the facts that 

 there is no relation between the recurrence of 

 drought in Southern India and the periodical 

 variation of the solar photosphere, but merely 

 that the interdependence of the two classes, of 

 phenomena, if real, is far from being simple and 

 direct, and also that other, and, as far as we 

 know, non-periodic causes concur largely in 

 producing drought. If we accept the conclu- 

 sions ... as to the highly probable periodi- 

 city of the Carnatic rainfall, one must admit 

 that there is, in that province, a recurrent 

 tendency to drought at eleven-year intervals, 

 though it does not always culminate in drought 

 of disastrous intensity ; and this epoch antici- 

 pates by about two years that of the snnspot 

 minimum. This tendency is much weaker in 

 other parts of the peninsula, and in Northern 

 India there is some indication of a tendency 

 to the recurrence of drought about the time of 

 maximum sunspots." 



The exact line of distinction between a clear 

 and a rainy day has never been clearly defined. 

 The Meteorological Congress of Vienna pro- 

 posed O'lmm. as the amount of precipitation 

 that should constitute the minimum for a day 

 to be designated as rainy, while the Inter- 

 national Committee in Paris of 1885, and the 

 Prussian Meteorological Institute fixed upon 

 - 2 mm. E. Bruckner has published a memoir 

 in which he proposes that all days be called 

 rainy in which the precipitation exceeds 

 0-15 mm., or 0-005 of an inch, and this whether 

 it be in the form of rain, snow, hail, drizzle, 

 mist, dew, or hoar-frost. He also recom- 

 mends, in more exact climatological researches, 

 a classification of the rainy days into several 

 grades according to their varying amounts of 

 precipitation. 



The most important feature in the meteor- 

 ology of the Puujaub, as shown in the report 

 for the financial year 1886-'87, was the failure 

 of the cold-weather rains (January to March). 

 Excluding the exceptional amount of 127'5 

 inches at Dharmsala (Jullundur), the greatest 

 annual rainfall was 53'3 inches at Abbottabad 

 (Peshawar), and the least 4*3 inches at Mount 

 Zaffargarh (Derajat). The highest tempera- 

 ture in the sun's rays was 183 at Lahore on 

 April 28, and it ranged from 172 to 175 in 

 the five succeeding months. The maximum 

 reading in the shade was 118 at two stations 

 on the 13th, and the lowest maximum was 

 79 at Sirsa (Delhi) in January. The absolute 

 minimum in the shade was 29 at Rawalpindi 

 in February, giving a range of 89 in the shade 

 temperature of the whole province. 



Observing during a certain period that the 

 rainfall of Italy was distributed in zones of 

 graduated degrees of intensity parallel with the 



Apennines, M. Ferrari studied the records of 

 previous years to determine the effect of the 

 mountains upon precipitation. He found that 

 when rain prevailed on the Mediterranean slope 

 of the peninsula and not on the Adriatic coast, 

 the center of low pressure was nearly always 

 in the north ; but when the rain fell on the 

 Adriatic slope without passing the Apennines, 

 the depression was in the south. In the former 

 case, the winds approach from the Mediterra- 

 nean side ; in the latter from the Adriatic side ; 

 and in both cases are drained of their moisture 

 by the summits of the mountains. It is known 

 that the amount of rainfall on mountains in- 

 creases with the height ; but this takes place 

 only up to a certain limit, when a maximum is 

 reached, from which there is a decrease going 

 both up and down. These relations were in- 

 vestigated by Erk on the northern slope of the 

 Bavarian Alps, from November, 1883, to No- 

 vember, 1885. He shows that a seasonal shift- 

 ing of the zone of maximum precipitation ex- 

 ists, which is dependent on the temperature of 

 the season. 



Storms. The Hon. Ralph Abercromby pre- 

 sented a paper to the Royal Society " On the 

 Relation between Tropical and Extra- tropical 

 Cyclones." All cyclones have a tendency to 

 assume an oval form ; the longer diameter may 

 lie in any direction, but has a decided tendency 

 to range itself nearly in a line with the direc- 

 tion of propagation. Tropical cyclones have 

 less tendency to split into two, or to develop 

 secondaries, than those of higher latitudes. 

 A typhoon that has come from the tropics 

 can combine with a cyclone that has been 

 formed outside the tropics, and form a single 

 new, and perhaps more intense, depression. 

 There is much less difference in the tempera- 

 ture and humidity before and after a tropical 

 cyclone than in higher latitudes. The quality 

 of the heat in front is always distressing in 

 every part of the world. The wind rotates 

 counter-clockwise round every cyclone in the 

 northern hemisphere, and everywhere as an 

 ingoing spiral. The amount of incurvature for 

 the same quadrant may vary during the course 

 of the same cyclone. The velocity of the wind 

 always increases as we approach the center in 

 a tropical cyclone, whereas in higher latitudes 

 the strongest winds and steepest gradients are 

 often some way from the center. The general 

 circulation of a cyclone, as shown by the mo- 

 tion of the clouds, appears to be the same 

 everywhere. All over the world unusual col- 

 oration of the sky at sunrise and sunset is ob- 

 served, not only before the barometer has 

 begun to fall at any place, but before the ex- 

 istence of any depression can be traced in the 

 neighborhood. Cirrus appears all round the 

 cloud area of a tropical cyclone, instead of 

 only round the front semicircle as in higher 

 latitudes. Everywhere the rain of a cyclone 

 extends farther in front than in rear. Cyclone 

 rain has a specific character, quite different 

 from that of showers or thunder-storms ; and 



