36 ; REPORT—1850. 
of this vapour, and in the month of January it is carried by south-western and 
western winds to those localities where the isothermal lines advance furthest towards 
the pole. It is accordingly to the condensation of this vapour, and not to the 
neighbourhood of the Atlantic ocean, in the latitude, that we are to attribute the high 
temperature of this part of the world in the winter. The Atlantic ocean is as near 
to Labrador as to Norway, but there is little condensation on the coast of the former, 
whilst there is much about the latter. Indeed, as far as we know, condensation of 
vapour is the only influence that operates exclusively on the eastern coasts of the 
two oceans, the Pacific and the Atlantic, and therefore to it we may attribute the 
warming of the localities, particularly in the Arctic ocean, as indicated by the iso- 
thermal lines. Condensation we know furnishes a constant and abundant supply 
of heat, not like diffusion by contact, nor radiation from surfaces nearly equal in 
temperature, but by the energetic chemical action which converts an aériform sub- 
stance into a liquid, and consequently changes the heat from a latent to an active 
state. 
The greatest irregular rise in the isothermal lines is found in the winter of the 
northern hemisphere, just at the time that the condensation of vapour produces the 
greatest effect on the temperature of the air. And the temperature rises the most 
along that line or stripe where the largest amount of condensation takes place; and 
in that locality the same temperature reaches the highest latitude, showing that con- 
densation of vapour is the cause of the rise of the isothermal lines in the parts. 
On the means of computing the Quantities of Aqueous Vapour in the Atmo- 
sphere at various places and heights. By Tuomas Hopkins. 
The author stated that meteorologists usually estimated the total amount of vapour 
in a vertical column of the atmosphere from the dew-point at its base, from which 
they inferred its tension, and thence the total quantity. This he asserted was an 
erroneous method, as it neglected the effort of the vapour expanding and forcing itself 
upwards through the air, a colder medium than would exist in each successive foot if 
nothing but the vapour itself were present. This opinion he illustrated by diagrams. 
On the Daily Formation of Clouds at Makerstoun. By Tuomas Hopkins. 
The author went into an examination of the meteorological registers kept at 
Makerstoun for the year 1844, to prove that the facts registered were in harmony 
with and tended to establish the theory he had advanced, that the horary fluctuations 
of the barometer were attributable to the daily vaporization of water by the sun, and 
the daily condensation of a portion of that vapour into cloud; the great difficulty 
being to account for the fall of the barometer from ten in the morning till four in the 
afternoon. At Makerstoun, the state of the atmosphere as to cloud was registered 
by noting an overcast sky by 10, a cloudless sky by 0, and intermediate states by 
intermediate numbers. The state of the wet- and dry-bulb thermometers was also 
regularly noted, showing both the activity of vaporization and the tension of vapour. 
On Meteorological Observations made at Kaafjord, near Alten, in Western 
Finmark, and at Christiania in Norway. By Joun Ler, LL.D., F.RS,, 
of Hartwell, Bucks. 
Alten.—Dr. Lee presented to the Association the meteorological observations 
which had been lately received by him from Mr. J. H. Grewe at the Alten Copper 
Mines in Norway. 
These observations are for twelve months, viz. from October 1848 inclusive to 
September 1849 inclusive; and although they form a continuation of previous ob- 
servations extending over a series of eleven years, yet in consequence of the alteration 
of the hours of observation, as also an additional number of daily observations (there 
being five daily observations, viz. at 7 and 11 a.m., 3, 7 and 10 Ρ.Μμ., instead of 
three, as formerly, at the hours of 9 a.m., 3 and 9 p,m.), they may be considered as 
