42 
BBPORT— 1847. 
On n Chart of tJie Dew-Point. By Capt. Sfiortbede. 
The number of papers alreatly before the Section being so great as toprediki 
separate communication, the President, at the conclusion of Dr. Lee's paper,ei- 
bited, ns on a kindred subject, a chart by Captain Shortrede, showing tbeniaiH 
which he has traced between the lemjveratureaofthedrv and moistbdbtinw 
ten and thedew.pnint. The chart conaUuofhoriioDtalimes.cufves.sodfintsdm 
diagonnily. The temperature of the air is counted on the horizontal 
prrssion of the moist bulb on the curves j the iatcrsecdonof these gire9apwiiii.».i- 
referred to the diagonals, gives the temperalwre of the dcw*poiot. Furlaaac* 
pressures ditFcrent from thirty inches, a correction is required.whichHmaioehi 
terai>erature of the air, ami consequently also on the depression, fnrwhicli 
simple rule. ITicn, with the temperature and depre-ssion bo corrected, the 
by inspection tlie temperature of the dew-point. The chart U prolraci«dfr»®»* 
lated quantities deduced from a strict analysia, after the method of Apjoim,®^^ 
the elasticity of vapour the tables deduced from the formula eihihitaltotitSecw: 
last year at Southampton. 
Btirofnetrical Levelings in the Madras Presidency. By General Cniir. 
with. Observations by Lt.-CoIoneI Sykhs, V.P.Ii'S. 
(Lionel Sykes exhibited and cxi»laine<l tw'o maps constructed by Major 
Cullen, of the Madras Artillery, comprising live sections of country, 
lativc levels, by baroinotj-iciU observation, at distances varying from kb 
miles; one section, from Cape Comorin to Mullai, at the source of the 
distance of about 1170 milc-s, pioceediug through Madua, Trichinopoly* 
Hyderabad, and Nagpore to Multoi; another from the Caves at Hion ^ 
lipatam, through Jngina. Beder, Golcondn. Condapilly to Masulipataffi. 
road-distance of 545 miles, llie second map contained three sectionsj ^ 
Nngparc to Jaulna, through Onnirawuttcc. of 265 wiles; Jl, 
Bcllary*, through Belgaum and Dharwar, 280 miles ; and a thiid, 
Mysore, through Sermgapatom, Bnogalore, Vellore and Arcot, 
miles. A third map gave bammctrical sections from Madras to 
line about W.N.W., 244 miles; and from Bellarv to Iddamaeul. <m s 
. by S., 1.56 miles. This map, without pretending to be a com^. 
aoction, showed the prevailing rocks on the route. Associated with “t 
were notices of the climate and mortality at most of the principal 
pming the maxima, minima and merui pressure of the barometer for 
the maxima, minima uud mean indications of the tlicrmometer; the j{f,. 
we nature of the monsoons; and the sickness and per-ccutage 
European and native trooi>8. The whole of these laborious results 
ordinary industry and judgement. Colonel Sykes’s object in exhibiting tw » 
was to call the attention of railway engineers to the use of thebaroroet^**, ^ 
curwr of the theodolite, in determining the general levcb of a country 
U> •clortjon of lines. He suggested also that geologists might ose the 
t o fix the height above the sea, of the strata described. He stated that ra 
the moderate oscillations of the barometer admitted of levels being 
Mme accuracy, even when the instrument was used independently; ^ ^ 
the mstrument used had been previously compared with a standard baro® 
TOntcmponuieous observations were made, he could testify from his own 
that a height so determined might not differ ten feet, when re-tested orre-»^ 
after n lapse of years. 
- • ^ 
dinprorcmetifs in ChroTio/nefcrSy and an improved method of 
applying I'cryfnc mre of Gold or Platinum for Astrotu>tsioo‘ ^ 
purjnmcs. By John (}oTTi.itB UhiifCH. 
audior described the principle, and gave testimonials of the nf.Vl'i- 
]astnr^ t'**ction chronometer balance, and detailedhis method of pracbsi^ 
i- « cynS'ounve?™™ '““‘y a wire of gold or platiou® 
