xviii REPORT—1848., 
they are in a satisfactory condition, the building having undergone recently - 
(on the representation by Mr. Ronalds to the Commissioners of Woods and 
Forests, in September 1847, of their necessity) such eternal repairs as suffice 
for its preservation, and that the instruments, such as are actually in use, are 
in good order and accomplishing the purposes of observation for which they 
have been constructed. An inventory of them has been furnished to the 
Committee by Mr. Ronalds, who is at present engaged in making out a com- 
plete catalogue of all the property of the Association on the premises. 
In reporting on the scientific objects accomplished since their last report 
in 1846, they consider that they cannot do better than to extract such por- 
tions of Mr. Ronalds’s reports above mentioned as bear upon this head. 
**The journal of ordinary observations has proceeded as usual; fourteen 
observations per diem have been pretty constantly set down of electric ob- 
servations. 
‘In the course of August 1846, many of the magnetic photographs were 
submitted to a rigid comparison with the corrected readings of the Greenwich 
magnet, and the result was officially declared to be ‘ highly satisfactory.’ 
“Tn the same month Dr. Banks brought an experimental specimen of his 
registering anemometer to Kew, and tried it at the north-eastern angle of the 
electric observatory. 
‘In September the third volume of Observations and Experiments was 
completed and carried to the Southampton Meeting of the British Association. 
‘** In December 1846, having by experience (since the beginning of August 
1845) found that my preliminary experiments, made upon a thermometer, a 
barometer, and an electrometer; each placed in the same camera or micro- 
scope alternately, fully warranted the cost of constructing apparatus of a 
durable and convenient character for each instrument, I began to make (at 
Chiswick) the photo-registering barometer, now at Kew, and spent. several 
months in its completion. It is furnished with a compensating apparatus 
(on the principle of the gridiron-pendulum), whereby the necessity of a cor- 
rection for temperature is certainly to a great extent, if not completely, 
avoided; it has one of Newman’s standard tubes, and the image of the sur- 
face of the mercury itself is employed totally unencumbered by any ball, plug, 
float, or machinery of any kind; the mercury is therefore as free to act in 
this as in any standard barometer. And it can be at any time used without 
the compensating apparatus, if that should be deemed objectionable. The 
same time-piece moves this and the magnetic apparatus. 
“In May 1847, the magnetic apparatus was improved by the substitution 
of new lenses by Ross in lieu of Voightlander’s. This enlarged the scale of 
declination. 
‘In January 1847, a complete electrical apparatus, exactly similar to mine 
in the dome at Kew for ordinary observations, was begun by Mr. Newman, 
by order of the East India Company, for the Bombay Observatory, and after- 
wards sent. Drawings were lent, instructions given, and electrometers made 
to correspond exactly with the Kew instruments. 
“In November 1846, drawings relative to Mr. Scott Russell’s experiments 
on the forms of vessels arrived at Kew, and I afterwards tried hard to get 
possession of the models themselves (in pursuance of a resolution of the As- 
sociation), but without success. 
“In May 1847, Mr. Hunt’s actinometer arrived at Kew. 
“In June 1847, the fourth volume of observations was completed and car- 
ried to the Oxford Meeting. 
* At this meeting some conversation, &c. occurred about establishing an 
end 
