PROGRESS OP METEOROLOGY IN 1889. 2(5 7 



Georgia a Inmiuosity sut'ticieut to plainly indicate the road to the 

 traveller in instances when low-lying dense masses of clouds involved 

 tbe whole firmament. In some cases the noctilucous condition may be 

 caused by the prolonged twilights due to the reflection of sunlight 

 from attenuated solid particles suspended in the supra-cirrus strata of 

 the atmosphere, and in other cases may be traced to cloud-obscured 

 auroral lights. Whether these sources of luminosity are sufficient to 

 explain the various observed phenomena without supposing a condition 

 of self-luminosity is still a matter of question. 



Mr. D. J. Rowan, Dublin, reports luminous night clouds appt^aring 

 between 10 p. m. and midnight, June 7, 1889, for the first time during the 

 present year. He has found them for several years to be an annual 

 phenomenon. {Nature XL, p. 151.) 



XIL— PERIODICITY AND SUN SPOTS; HYDROLOGY; FORESTS AND CLI- 

 MATE ; CLIMATES OF GEOLOGIC EPOCHS. 



Sun-spot period in Indian weather. — Mr. Eliot in his last Meteorological 

 lleport for India, referring to sun spots and weather in India, says that 

 the period of minimum sun spots is apparently associated with the larg- 

 est and most abnormal variations of meteorological conditions. Thus 

 exceptionally heavj^ snow fell in the northwest Himalayas in 1866, and 

 again in 1876 and 1877: the most disastrous famines of recent years in 

 India have occurred near the period of minimum sun spots ; and the largest 

 and most intense cyclones apparently have a tendency to occur shortly 

 before the minimum. For example, in the great Calcutta cyclone of 

 1864, 60,000 people were drowned, and in the still larger Backerganj 

 cyclone of 1876, 100,000 lives were lost by drowning. 



Hydrology in Galicia. — Annual tables of rainfall and river heights in 

 Galicia for 1887 and 1888, have been published (see bibliography) under 

 the direction of Professor Karlinski, director of the Cracow observa- 

 tory. The volume for 1887 contains daily observations of river heights 

 atsevenly-two stations and precipitation measures at one hundred and 

 thirty-five stations; that for 1888, ninety-two river stations and one hun- 

 dred and twenty-nine rain fall stations. The daily rainfall tables are 

 given only for June in 1887, and in 1888, for July, August, and Septem- 

 ber. Isohyetals are drawn presenting graphically the distribution of 

 rain-fall. The tables furnish a valuable contribution of data for the 

 study of the relation of surface and climatic conditions to the flow of 

 streams. 



Hydrology of the Saale.—T)r. Ule (Halle) has investigated the relation 

 of the discharge of the Saale to the total precipitation over its water- 

 shed, as determined by reports from forty-five stations. He fiiuls that 

 for the period from 1883 to 1886 only 30 per cent, of the precipitation 

 was discharged by the Saale. The total annual precipitation was 606 

 millimeters; no evaporation observations were made. {Meteorologische 

 Zeitschrift, 1880, vi, p. 272.) 



