XXXII 
REPORT -1854. 
the intention of your Committee to direct that a new cathetometer should be 
constructed in the Observatory on more exact mechanical principles. 
The number of instruments now in course of verification, under the 
directions of your Committee, is : — 
For the U. S. Navy .... 1000 thermometers. 50 barometers. 
„ Board of Trade.. 500 ,, 60 „ 
Definition of the. Boiling-Point of Water .—Your Committee, at the last 
meeting of the Association, were requested to furnish a report on the de¬ 
finition of the boiling-point of water at present adopted in this country for 
the thermometric scale. This has already been considered by the Commis¬ 
sioners appointed by Government to construct Standard Weights and Mea¬ 
sures, and in the Report they have presented to Government during the 
present year, they have defined 212° upon Fahrenheit’s scale to represent 
“ the temperature of steam under Laplace's standard atmospheric pressure, or 
the atmospheric pressure corresponding to the following number of inches 
in the barometric reading, reduced to 32° F., — 29*9218 + 0-0766 X cosine 
(2. latitude) + (OOOOOOl 79 x height in feet above the sea).” Your Committee 
recommend that, this definition he adopted. In accordance with this defi¬ 
nition, the standard pressure under which the boiling-point of thermometers 
■will have to be determined will bo,— 
At 32° P. 
J n Ro, , ldon . 29-905 -f (0-00000179 x height above the sea). 
In Dublin .29-900 „ 
In Edinburgh.29-893 „ ” 
The small additional correction for the height above the sea level in- 
cluded m brackets, may be, however, neglected, being insensible at any 
part ot the three towns mentioned. 
notboo, a Sooked. hei8hla be ‘' e 8ive “ are 32 ° F ” “ d t,lis correctifiD musl 
b^^.^”'^ e 'S7rT The Station of standard thermometers has 
last meetinrr f e s . *’ . and ~ 1 ,nstr umente have been issued since the 
mete " s ",nLdtnthe A S s°c.at ,o nmaking a total of 91 standard thermo¬ 
meters supplied to institutions and individuals. 
as ofthermomete^^bv^rnn the errors of barometer as well 
structed at the Obi-rvatc^rv and a.?** 8ta,,dard ® al Kew > has been con- 
will be given by Mr Wekh ‘ detailed account of the processes employed 
Association. ^ * n a 8e P®rate communication to the British 
year—For thc°EiS! InSw Compau^ be ** examincd d « rin 8 the P ast 
hygrometers, and 4 barometenJ ‘for* M?,. t !'® r,nol *\« !te « for 29 of Regnaults 
mometerai tor Hobart on thi rrevandrnm Observatory, 8 ther- 
«■ Kitts, 5 theiTOomefcers- b for'th^Svdrn Prin V mct< r rs * for A *M^dleship, 
ammeters and 1 barometers- for Si gr £ P .\ Pr ? f the Admiralty, 16 ther- 
6 mountain barometers, 9 aneroid ba S c lda S 1 n 1 we > >- 93 thermometers, 
6 boiling-point thermometers. ' et€rs » *0 ground thermometers, and 
the standard weigh^'ma < df.~h^ ,,ave reported last 
r. Miller, of King’s College were at \\ ^ rt ^ m S> under the direction of 
of Cambridge, for verification a nd \T le 1,1 hands of Prof. Miller, 
Messrs. Trpughton and Simms, was with the I* 6 standar 1 d scaIe prepared by 
* lth the Rev * Mr. Sheepshanks, for com- 
