XXXIV 
REPORT- 1854. 
proximation is made towards the conditions necessary to obtaining the true 
temperature of the air. Meteorological observations have been made since 
1st January 1854, at 6 and 10 a.m., 2, 6' and 10 p.m. 
In respect to the two forms of maximum thermometers now named, it may 
be stated that they have both been found to perforin in a very satisfactory 
manner; the very ingenious instrument of Messrs. Negretti and Zamira 
has one quality, which, as regards durability, places it above every other 
form of maximum thermometer, for when onco well constructed, it can 
never get out of order; it is somewhat difficult in construction, and conse¬ 
quently more costly, but the observer, having first satisfied himself ns to itt 
correctness, may ever afterwards use it with confidence, relying that his 
register will not be interrupted by any of those annoyances to which he may 
have been accustomed in other forms of this instrument. The plan of Mr. 
Phillips is most valuable for its extreme simplicity ; it is capabh of greater 
delicacy of indication than even Negretti’s, and in the hands of an observer 
who treats his instruments with care, will continue to perform very accurately 
for probably an indefinite length of time. The only case in which this form 
of the instrument might, be found to fail, would probably be in carriage or 
when otherwise exposed t.o violence: any thermometer, having an overflow 
chamber at the fop of the tube, can be readily converted into a maximum 
with the aid of a spirit-lamp, and if the instrument should bv any chance get 
out of order, it can as easily be remedied. Any careful observer, who is not 
atraid to handle a thermometer, will, it is believed, find this the most conve¬ 
nient form, of all maximum thermometers. As an instrument for general 
use, and HI the hands of persons unskilled or careless in the use of thermo¬ 
meters, its expediency may however be more doubtful. 
SMZ\StJT ra/)/ ! ,, \ ** egist£r (hc S P« ts on the Sun's Disc.— Colonel 
Rested*to a hiir^ihn^' 0r ^ CC ^ /° Committcp tlmt Sir John I lerscl.el had sug- 
Iraphic nietur^nf t? arrangements being made for a daily pboto- 
?ouV CiJmSK * hwin P ,he &c„ it was resolved by 
Ms s,:s:& "■ *-*■ 
“ My dea n Sm t . . , - “32 Harley Street, April 24, 1854. 
importance to secure at slm! ° co " s 'der *t an object of very considerable 
different localities, d ai W pZocraS ^ ind °* ■d at more than one, in 
to keep up a couaecutive^mirl nJlr ",i '^P^sentations of the sun, with a view 
marking out on it, in mf. renee ♦ delineation of the whole disc and the 
through its centre, the places, sizes and^rf 8 ^ ^ 1 the e ‘l uinocti al passing 
I should imagine no very powerful teles*" 9 °* t,u : s P°k» there would need 
should be equatorially mourned , °P e ; d m te the contrary : but it 
paral cl The imagedbSrli^ f to have a <*** «M*Sn in the 
bc formed ’ not in the focus of the pa , p<>r ( or c '°P°dionized glass') 
lens drawn out somewhat beyond the °^^ ct ' | ens, but in that of the eve- 
ways to the same in variable distance * P ° r s,tuation for distinct vision (and 
smfmlrf 3 / ' this arrangement^ coS^Y." 
thrown tf an y of mires in S ‘ r n " b ) r 'Unified image of the 
e teW POn d, V focusing glass’Tf ie^n °T ° f t,,L ‘ ob J^t-glai may bc 
cuW o S ,PC V liy e “P^yiug a system o r!^ b0J 5. a,, jt“ted kl & eve-end of 
° tlm d,Urual ‘notion, g and‘so Zpol^Z * nd 
posed as to divide the field of view 
