26 REPORT—1852. 
equator; and many of the stations are at very different elevations, which it is 
known affects both the annual and the daily oscillations. Dr. Buist in his paper 
discusses the exceptional cases to the supposed rule, and recommends them for 
scientific consideration, 

Communication from the Smithsonian Institution ‘on the Plan adopted for 
investigating the Meteorology of North America. 
Col. Sabine read a letter from Prof. Henry, of the Smithsonian Institution. 
Accompanying the letter was a set of charts to illustrate the plan adopted by the 
Institution. They gave the atmospheric changes in pressure, temperature, and 
wind during a storm which commenced at the close of January 1851. The prin- 
cipal object of this communication was to cause the British Association to procure 
the establishment of a series of observations in the British possessions on that con- 
tinent which may serve as an extension of those proceeding under the direction of 
the Smithsonian Institution. The general plan is that originally proposed by Prof. 
Mitchell of North Carclina, and used successfully by Prof. Loomis in the study of 
two storms which occurred some years since. It consists in ascertaining the changes 
of the several meteorological elements from the mean of the month in which the 
storm occurs, and delineating on a series of charts all the phases and movements of 
the atmosphere from the beginning of the disturbance to its end. As many of the 
instruments used had not been compared and were not of the most improved con- 
struction, it had been feared that no reliable results could be obtained. But this is not 
the case: though the absolute mean temperature and pressure are not obtained, yet 
facts of equal, if not greater interest, are deducible, namely, the changes from a 
normal state. Thus the average (say for a month) can be deduced with sufficient 
precision to afford important practical deductions. Though the zero-points may be 
in error several divisions of the respective scales, they may give with sufficient accu- 
racy the changes which occur at a given time, and thus furnish reliable data for de- 
termining the dynamic phenomena of the atmosphere, though inadequate to furnish 
statistical meteorological elements, The whole number of observers immediately 
under the direction of this Institution is about two hundred; and a hope was ex- 
pressed that the British Association and the Royal Society would aid by their co- 
operation in extending the system by establishing corresponding observations in Her 
Majesty’s possessions in America. 
On the Aurora. By Lieut. W. H. H. Hoover. 
The author believes the aurora borealis to be moisture in some shape (whether dew 
or vapour, liquid or frozen), illumined by the heavenly bedies, either directly or | 
reflecting their rays from the frozen masses around the pole, or even from the imme- 
diately proximate snow-clad earth. This opinion he endeavoured to support by 
facts and argument. 
Notes on the Meteorology of Ireland, deduced from the Observations made at 
the Coast-quard Stations under the direction of the Royal Irish Academy. 
By the Rev. H. Liuoyp, D.D., FR. 
In the year 1850 an application was made by the Royal Irish Academy to the 
Government, requesting that meteorological and tidal observations should be made 
by the officers of the Coast-guard Service, according to a prearranged plan, at cer- 
tain selected stations on the coasts of Ireland, the Academy undertaking to furnish 
the instruments and the instructions for their use. This application was promptly 
acceded to by the Government; and in the course of the same year meteorological 
instruments, previously compared with the standards belonging to the Dublin Mag- 
netical Observatory, were conveyed to the several stations, and tide-gauges of a new 
construction were erected. All the stations were subsequently visited by Members 
of the Council of the Royal Irish Academy, who undertook the task of placing and 
adjusting the instruments, and of training the observers in their use. At the same 

