aie 
ON MAGNETICAL AND METEOROLOGICAL OBSERVATIONS. 55 
nomena of disturbances. They have been shown by the Toronto observa- 
tions to follow a certain order, in frequency, in force, and in direction, con- 
nected with the hours of the day. The comparison of the observations at 
Toronto and Van Diemen Island, in the volume of ‘ Unusual Magnetic Dis- 
turbances,’—the intercomparison of the observations at the several European 
stations in the ‘Resultate’ of MM. Gauss and Weber,—the comparison of the 
American stations with each other and with a European station in the Toronto 
volume,—have all shown that highly interesting and important conclusions are 
derivable from this class of observations. It cannot be doubted that a more 
general and elaborate examination of what has been already done, will both 
add to the number of these conclusions, and will point out special problems to 
be solved by a continuance, and possibly by some modification, of the system 
of simultaneous observation. Meanwhile it may perhaps be desirable to dis- 
continue, for the present at least, pre-arranged term observations, and to sub- 
stitute for them the most comprehensive and assiduous observation of the 
phenomena at times of great disturbance that the strength of each observa- 
tory will permit; holding all things ready, however, to cooperate in any pro- 
position of conjoint observation, that may grow out of the further examina- 
tion to which the great body of observations already collected will doubtless 
be subjected. Whilst the Arctic Expedition is in the northern seas, the 
phenomena during periods of great disturbance ought to be particularly at- 
tended to at stations in high magnetic latitudes in Europe and America, and 
specially at Toronto; as, should the Expedition be detained during a winter, 
their instruments will be established in a locality which may render simulta- 
neous observations of extraordinary interest and value. ~I think also that it 
may be more advantageous on some occasions to observe the precise instants 
of the occurrence of remarkable phenomena, than to record the indications 
of the instruments at fixed intervals of regular recurrence. 
Il. Meteorological Observations—The periods during which hourly ob- 
servations have been maintained at our observatories is probably sufficient in 
the greater part of instances to meet the problems now presenting themselves ; 
if so, the attention bestowed on them might now be advantageously directed 
to observations having more special objects in view. I feel by no means con- 
fident, however, that more than three and a half years of hourly observation 
may not be desirable at Toronto, to meet questions which, if not already be- 
ginning to be considered, are not unlikely to be so in the rapid march which 
this science is now making; and I am inclined to think that it may be ex- 
pedient that there should be a full series of at least five years of hourly ob- 
servation, obtained at some one station in Europe and another in America; 
and that for the latter, Toronto is remarkably well situated. 
There are a variety of special problems requiring systematic observation, 
of which the solution is extremely important in theoretical respects, and in- 
dispensable if anything like completeness is desired in the record to be left 
by our observatories. 1°. The separation of the pressures of the air and vapour, 
which united constitute the barometric pressure, has only been feasible since 
the invention of instruments to measure the tension of the vapour. The facts 
which this most important addition to our instrumental means has disclosed 
in the different observatories, some portion of which is already before the 
public*, are sufficient to show that a new era has opened in scientific meteor- 
ology ; that observations conducted as they have been at the observatories 
reveal as their immediate fruits the laws of the periodical and systematic va- 
riations of the aqueous and gaseous pressures, and their connection with the 
variations of the temperature and those of the direction and force of the wind. 
* Brit, Assoc. Reports, 1844, pp. 42-62, 
