298 REPORT—1858. 
submitted for your Committee’s inspection, and in both which the fluctua- 
tions in question emerge in a very satisfactory manner, and one calculated 
to give a high idea of the precision of which such determinations are 
susceptible, when it is considered that the total amplitude of oscillation due 
to this cause in the direction of the Cape-needle is only about 18” of angle. 
Your Committee, looking at this long catalogue of distinct and positive 
conclusions already obtained, feel themselves fully borne out in considering 
that the operation in a scientific point of view has proved so far eminently 
remunerative and successful, and that its results have fully equalled in im- 
portance and value, as real accessions to our knowledge, any anticipations 
which could reasonably have been formed at the commencement of the 
inquiry. 
Having satisfied themselves of the great and important value of the results 
already obtained, independent of the dormant interest as respects future dis- 
cussion which the mass of observations accumulated continues to possess, 
and which it remains for future theoretical combinations to elicit, your 
Committee next turned their attention to the question whether, and to what 
extent, the maintenance of some or all of the old Colonial observatories, or the 
establishment of new ones for a limited term, might be expected, first, to give 
additional certainty and precision to the determinations already obtained, 
and secondly to elucidate points imperfectly made out, and more especially 
geographical relations which determine the greater or less amount of dis- 
cordance between the epochal hours of the regular and irregular diurnal 
changes—relations which, no doubt, involve the causes of the irregular 
fluctuations themselves (causes at present involved in the greatest ob- 
scurity )—and to obtain indications of the points in the earth’s surface at 
which the forces producing them originate. 
As regards the general question as to the desirableness of some continua- 
tion of the observations, its seems hardly to be referred to our consideration 
as a Committee,—the resolutions come to both by the British Association 
and by the Council of the Royal Society, in the appointment of their 
respective Committees of co-operation, indicating an opinion already con- 
clusively formed on the part of both bodies to that effect. They have felt 
it due to themselves, however, to come to an independent conclusion on that 
point; and having done so with perfect unanimity, on the grounds already 
adduced and the expectations for the future which those grounds justify, 
they next address themselves to the consideration of the two points above 
indicated, and to the important questions, first, whether to recommend the 
continuance or resumption of the establishments at the former stations, or 
the selection of new ones; and secondly, with how few new or revived 
establishments, with how limited a scale as to extent and expense, and with 
how short a period as the minimum term of their duration, the expecta- 
tion of these advantages being secured could be compatible; and finally to 
fix upon the stations most desirable. 
As regards the first point referred to, viz. the more complete establish- 
ment of the laws themselves, and the giving of greater numerical precision 
to their expression, the Committee is of opinion that the laws themselves 
are not likely to be subverted or contradicted by a larger series of obserya- 
tions at any station for which they have once been shown to prevail; but 
that every new station differing much in geographical situation from the 
‘former in which they might be found verified with or without supple- 
mentary modifications, would undoubtedly add strength to the induction by 
‘which they have been concluded. Additional numerical precision, on the 
other hand, would only be attained by a continuance of observations at 
