466 
Abstract from a Meteorological 
comparison made with two mountain barometers, of Newman’s 
construction, which had previously been compared with the 
Royal Society’s barometer, it stood -0505 inch lower than the 
Royal Society’s barometer; so that the reduction to that stan¬ 
dard has been made, as also the reduction to the half-tide level. 
The rain gauge and evaporating dish were placed together, 
sheltered from the sun’s rays by a roof supported by brick pillars, 
so that the latter was completely exposed to the state of the 
atmosphere, and gave results as near as instruments of this kind 
could be expected to give; being placed together, and of the 
same size and shape, their results were at least proportionate to 
each other. During the first three years of the period, the 
evaporation was registered at each of the hours of observation • 
but for the last two years, only at nine o’clock in the morning, by 
which the daily evaporation was ascertained. 
From the table the following results have been ascertained :_ 
Temperature .—For the whole period the maximum and mini¬ 
mum temperatures were respectively 108° and 35°, being a range 
of 73°. The greatest annual range occurred in the year 1845- 
viz., 72°5, whilst during the previous year it only measured 52°7 
The hottest month was January, the thermometer ranging 
between 107°5 and 60°; the coldest month, July, the thermo¬ 
meter at from 75° to 37®. 
The difference between the dry and wet thermometers was 
greatest in the month of November, and least in June; the 
former being 6°1, the latter 1°7. 
Supposing that the hour of nine in the forenoon gave the mean 
temperature, the monthly mean temperatures are as follow :_ 
January .74.4 July.52-9 
February .74-1 August . 54.4 
March. 71 - o September.go-l 
April.65-2 October . 05-4 
May. 68'6 November. 72-7 
June.52 - 9 December. 73-4 
Whence the mean annual temperature is 64®63. 
The Pressure of the Atmosphere .—For the whole period the 
barometric column ranged between 30-603 inches and 29-231 
