Contributions to Meteorology, 279 



prevalent the S. The aggregate amount linear in miles run was 

 41,338.60 miles, which shows a decrease of 13,086.50 miles com- 

 pared with last year, and a decrease of 11,723 03 miles compared 

 with 1856. The yearly mean velocity was 4.613 miles per hour, 

 which is 1.567 miles less than the mean annual velocity for 185*7, 

 The maximum velocity was 37.70 miles per hour. January was 

 the most windy month, and September the calmest. 



The greatest Intensity of the Sun's Rays .as 117°, and the 

 lowest point of terrestrial radiation, 31°. 2 below zero. 



The yearly amount of Dew was considerably below the usual 

 mean amount compared with a series of years. 



There were 56 days perfectly cloudless, which is 25 more than 

 the cloudless days of 1857. There were 118 nights suitable for 

 astronomical purposes. 



The Aurora Borealis was visible at observation hours on 39 

 nights. Lunar Haloes were seen on 4 nights. The Zodiacal 

 Light was very bright in February, but since then has exhibited 

 no special appearance. Parhelia were visible on 2 days. 



The Eclipse of the Moon was visible on the 27th February. 

 The Eclipse of the Sun was invisible on the 15th March owing to 

 cloudy weather. 



The winter of 1857-58 fairly set in on the 22ud December 

 1857. 



Ozone. — The amount of ozone during the year has shown an 

 increase on the usual average. Observations are now being taken 

 here, intended to shows the effects of the different coloured rays 

 of light on the Ozoneometer, and also the effects of vegetation on 

 the amount. 



Atmospheric Electricity. — The tri-daily observations are still 

 continued in this important branch of science, the amount indicated 

 in frequency and tension is very near equal to the amount of last 

 year, but is nevertheless rather below the usual average. The 

 Romershausen apparatus seems pretty well adapted for the pur- 

 pose of collecting atmospheric electricity, bnt is inferior to the 

 large apparatus which is erected here, both as to collecting and 

 retaining the electric charge. 



The Song Sparrow (Fringilla Melodia) the harbinger of spring, 

 first heard on the 10th March. Swallows (Hirundo Rufu) first 

 seen the 15th April. Frogs (Rana) first heard the 15th April 

 (this is about a week earlier than usual,) Shad (^4 losa) first caught 

 29lh May. Fire-flies (Lampyris Corusca) first seen the 18th of 



