their internal motions if any, the number of strata which may F 
detected, and the number and direction of the currents a 
cy their motion may indicate, will also form interesting objects of — 
, observation in conjunction with the preceding. _Cotemporaneous’ 
3 observations will of course be made on the earth, during the time we 
, of the aérostatic voyage, which will possess a greatly increased , 
interest if circumstances shall permit it to take place on the day 
when hourly meteorological observations are made at all the prin- 
cipal observatories of Europe, according to the plan laid down by 
Sir J. Herschel. Portions of the air should be brought down, 
for examination, from the highest elevations; and this may prob= 
ably be best effected by taking up several glass balloons or bottles. 
carefully gauged, fitted with stop-cocks, and filled with water. 
The water should be allowed to run out at the proper station, and 
the stop-cocks closed. Experiments upon the radiation of heat 
would be interesting, although there are probably no known 
means of instituting them with all the accuracy which could be 
desired. 'To these observations might be added, others of great 
interest upon the electricity of the atmosphere, by dropping wires 
into clouds, or from stratum to stratum of cloudless air, and ex- 
amining the nature of the electricity of their extremity by means 
i of a very delicate electroscope, but the observer’s attention must 
not be distracted by a great variety of objects. It would be de- 
. sirable that two observers, stationed at the extremities of an accu- 
rately measured base, should take the altitudes of the balloon, at 
the instants the observations of pressure and temperature were 
, made. 
i . The committee, of which Sir J. Herschel is chairman, for su- 
perintending the scientific codperation of the British Association 
in the system of simultaneous observations in Terrestrial Mag- 
netism and Meteorology, made a report, of which the following 
is the principal part : 
_ Your committee, referring to their last report for the history of 
the magnetic operations in progress up to that time, have to state, 
in continuation, that the magnetic observatory at St. Helena was 
finished, and the instruments established in August, 1840,—at 
Toronto in September, and at Van Diemen’s Land in October of 
the same year. The observatory at the Cape of Good Hope was 
completed and in activity at the commencement of March in the 
current year, under the superintendence of Lieut. Eardley Wil- 
