406 
POPULAR SCIENCE REVIEW. 
METEOROLOGY. 
Isothermals of the British Isles for July and January. — This is a subject 
upon which all feel interested. It has been well treated by Mr. A. Buchan, 
in the Journal of the Scottish Meteorological Society for January, 1864. 
ITis paper is accompanied by a map, upon which are seen two series of 
lines, one in blue, the other in red, which represent respectively the equal 
heats of various localities in January and July. The data upon which 
the conclusions drawn have been founded are taken from the reports of 
the various Meteorological Societies existing throughout the country. 
The numbers given stand for the temperatures at the sea level ; and hence, 
in order to calculate the exact heat, it will be necessary to subtract one 
degree of Fahrenheit for every 300 feet elevation. With regard to the 
lines of equal summer heat, there are some points which deserve special 
attention. The general slope of the lines is from north-east to south-west, 
which indicates that the eastern portion of the British Isles enjoys a higher 
summer temperature than that which lies to the west. This is due to the 
fact, that the prevalent wind in July is westerly, and, coming over the 
Atlantic, renders the west coast cooler than the east ; and also to the 
circumstance, that the clouds in the west are greater in volume and lower 
than those in the east. The curving northward of the lines in the central 
portion is due to the width of the land, which allows the middle portions 
to have more of a continental temperature than the borders. The high 
winter temperature of the west coast is due to three causes : — (1) The 
warm south-west wind, which loses some of its heat before reaching the 
east coast. (2) The larger amount of vapour deposited in rain on the 
west coast (nearly double that in the east), which thus liberates a very 
large quantity of latent heat. (3) The larger amount of vapour in the 
west, which obstructs radiation, not only when in a visible state in the 
form of clouds, but also when dissolved through the atmosphere in an 
invisible state, in which condition, as shown by Professor Tyndall, it 
prevents the radiation from the earth of the heat which has been absorbed 
from the sun. 
Non-Cy clonic Character of the Storm of October 29, 1863. — The Rev. 
Samuel Haughton addressed a letter to the Royal Irish Academy, at its 
sitting in November 30, in which he shows that this storm was not a true 
cyclone. He says, the wind in Dublin blew steadily from the south-west 
during, and long after, the gale ; while in Armagh it seems to have shifted 
through 132 degrees from 10 a.m. to 1 p.m. The gale in Dublin was at its 
height at 11 a.m., when the wind travelled at the rate of sixteen miles per 
hour. Perpendiculars drawn to the directions of the wind at this hour, 
from Dublin, Armagh, and Ballinasloe, nearly intersect in Lough Melvin, 
in the county of Fermanagh (a circumstance which at first sight would 
seem to prove that the storm was a cyclone). But if a line be drawn 
parallel to the bisector of the angle produced by the direction of the wind 
at Armagh, at the hours of 10 a.m. and 1 p.m., it is well known that the 
gale should have travelled along this line. If this had been the case, the 
