TRANSACTIONS OF THE SECTIONS. 15 



sistance, E. At the junction between the end of the cable and the resistance II a 

 key is attached, whicli is connected by either the reflecting electrometer or a re- 

 flecting galvanometer with the slides". That position is sought upon the slide 

 which has precisely the same potential as that of the cable at the point where it 

 joins the resistance E. If now the potential of the battery be represented by j), and 

 the resistance of the junction of the cable with E be represented hj p^, and if the 

 two portions of the coil necessary to balance this potential be n and m, it will be 

 evident, on the principle of the "NMieatstoue Balance, that n:m::Ii: cable .r (the 

 cable resistance ) . Thus, then, the resistance E being known, 2> and p^ being Imowu, 

 and the resistance or position on the slide noted, the resistance of the cable is accu- 

 rately obtained. 



Meteoeologt. 



On the Climate of Aldershot Camp. By Sergeant Aenold, F.M.S. 



The military station of Aldershot is in the countj' of Hampshire, bordering on 

 Surrey, and is" situated on an elevated site, about 320 feet above the level of the 

 sea. It is distant about 40 miles from London, and about 50 fi-oni Portsmouth and 

 Southampton, being in lat. 51° 15' 25" N., long. 45° 36' W. The extensive area 

 of ground occupied by the North and South Camps was formerly a barren heath, 

 the soil consisting mostly of sand and gravel, covered by about seven inches of peat. 

 On the north and south the Camp is much exposed : on the east it is slightly 

 sheltered by hills that rmi from the eastern boundary of the North Camp to the 

 Soiith. On the south-east is a range of hill, called' the " Hogsback ; " these are 

 the highest in the neighbourhood, attbrding great protection to the cultivation of 

 hops, which is carried on so successfully that their growth is rapidly extending. 

 The north-west and west are bounded by land under cultivation. Small woods or 

 copses are numerous in the locality, consisting principally of stimted fir-trees and 

 brushwood. A small river named Blaclcwater is the only one in the vicinity. 



Meteorological observations during tlie past eight years yield the following 

 results : — The mean height of the barometer at 325 feet above the mean sea-level 

 is 29-610 inches ; this, however, is only an average of seven years, a standard in- 

 strument not having been used for the whole of 1858. The highest observed 

 reading of the barometer was 30-452 inches on Januai-y 9th, 1859 ; the lowest, 

 28-269^ inches on January 14, 1865 (these observations being reduced to 32° 

 Fahrenheit). The adopted mean temperature of the air is as follows : — January, 

 88°-4; February, 39°; March, 42°-l ; April, 48° -4 ; May, 5.3° -2 ; June, 58°-8 ; 

 July, 59°-9; August, 59°-9 ; September, 56°-6 ; October, 51°-5; November, 41'-'-8; 

 December, 40°-3. The mean for the past eight years is 49°-2. The mean of all 

 highest readings is 57" -0, and the mean of all the lowest 41°-9 : the mean daily 

 range of temperature being 15°-8. The highest temperature was 93° on July 12, 

 1859, and the lowest 8° on December 29, 18G0, so that the extreme range of 

 temperature is 85°. The mean degi-ee of humidity (saturation= 100) is as 

 follows :— January, 89°; February, 82°; March, 84°; April, 76°; May, 78°; 

 June, 78°; July, 78°; August, 78°*; September, 85°; October, 86°; November, 90°; 

 December, 89°. The yearly mean is 83°. The amount of cloud is estimated on 

 the usual scale, being a clear sky, and 10 an overcast sky. The mean amount is 

 O-l. The month in which the largest amount of cloud occurred was December (7-2), 

 and the least (5-1) in September. The indi-^-idual monthly averages show that the 

 most cloud state (8-5) occurred in December 1805, and the least (3-2) in Jime 1859. 

 Eain falls on an averase of 143 days of the year. The greatest number of days 

 was 183 in 1860, and ithe least 11-3 in 1864. The average yeariy rainfall is 25-24 

 inches. This is less than at any other station in Hampshire. The greatest yearly 

 total was 33-89 inches in 1860, the least 17-13 inches in 1858. The greatest 

 monthly fall was (5-80) in October 1865, and the least (0-16 inch) in February 

 1858. Taking the average of eight years, the wettest month is October, the mean 

 amoimt being 2-96 inches, and the driest February, being 1-23 inch. The mean 

 monthly amount of ozone is 1-7 ; the largest quantity occiu'red in IMay, the mean 

 of -which is 2-2. and the least 1-1 in December. The yearly relative propor- 



