REPORT OF THE KEW COMMITTEE. XXXill 
ciation has shown me in their magnificent Meeting. I shall never forget the 
help afforded to me in so many different ways, and I desire earnestly to put 
it in immediate contribution towards the advancement of science. 
“The Observatory of Coimbra must have in its library, as a memorial, the 
valuable collection of Transactions of the British Association, and I hope that 
you may be so kind as to put me in the way of obtaining these volumes. 
«‘T remain, dear Sir, 
«« Sincerely yours, 
“J. P. Gassiot, Esq.” ‘«« JactntHo A. DE Souza.” 
The request of this letter has been complied with by the Council of the 
Association, and a complete set of the Transactions has been dispatched to 
Coimbra. 
The Director of the Lisbon Observatory has since requested the Committee 
to superintend the construction of a set of self-recording Magnetographs. 
The Committee, in complying with his request, have made arrangements for 
the instruments at present exhibited in the International Exhibition, and 
these will afterwards be mounted at the Kew Observatory for inspection and 
verification. 
A Differential Declinometer for the Government Observatory at Mauritius 
has been verified and forwarded to Prof. Meldrum, who has received it in 
safety. 
Gini, Rokeby, of the Royal Marines, already favourably known by a me- 
teorological register very carefully kept at Canton during its occupation by the 
British troops, has received instruction at Kew in the use of magnetical in- 
struments, and has been furnished with a Dip Circle, a Unifilar, a Bifilar, 
and a Differential Declinometer, of which the constants have been deter- 
mined at the Observatory. Lieut. Rokeby proposes to employ these instru- 
ments at the Island of Ascension during his term of service at that station. 
He has also been furnished by Admiral FitzRoy with a complete equipment 
of the meteorological instruments supplied by the Board of Trade. The 
importance of Ascension as a magnetical station has long been recognized. 
Situated very nearly on the line of no magnetic dip, the determination 
of the periodical variations and of the secular changes of the three mag- 
netic elements cannot fail to possess a high value; and as a meteorological 
station, a rock in the mid-ocean, within 6° of the Equator, presents an almost 
unrivalled locality for an exact measure of the amount of the lunar atmo- 
spheric tide, and of the variations in direction and force of the trade-wind. 
The Admiralty, apprised of Lieut. Rokeby’s meritorious purposes, have sane- 
tioned the appropriation of the officers’ quarter at the summit of the Green 
Mountain, known as the “ Mountain House,” as an observatory; and the 
department of the Board of Trade, under Admiral FitzRoy’s superintendence, 
has authorized the expenditure of £50 in providing the additional accommo- 
dation required for the instruments. Lieut. Rokeby has arrived at Ascension. 
with the instruments uninjured, and writes in strong terms of the support 
he receives from Captain Barnard, the commander of the troops on the island. 
On June 19th the Chairman received a letter from the Astronomer Royal, 
in which he stated that he was very desirous of comparing the Greenwich 
records of the vertical-force magnet with those at Kew; and that, if agree- 
able to the Committee, he would request Mr. Glaisher to endeavour to arrange 
a meeting with Mr. Stewart for that purpose. 
The Chairman immediately replied, offering every facility, and Mr. Glaisher 
has since visited the Observatory, where the comparison has been made. 
1862. ¢ 
