1833.3 Miscellaneous. 655 
above amount (by 2. 12 times) to 3,630 times, but taking the general average heat 
of the air, in the shade, in hot countries, at 70° only, the amount would be 7-10ths 
of the above, ==1200 times nearly; while for England, assuming 50° as a mean, 
we have one half of the 1712=856 times excess of heat of the comet of 1680, over 
that of iron raised to a glowing red : this is tolerably near the 900 times mentioned 
by the Burmese prince ; but the medium heat of air, out of doors in the shade in 
England, is about 51, 4°, so that, multiplying 1,712. 554 above mentioned, by 
51,4 = 514 we get 8804 for the excess of heat, differing only by 193 from the 
answer sought: but we get it nearer, by using the 100dth. part of the mean heat 
of the thermometer, out of doors, = 51,4 and of that within doors, 52.9 mean = 
52-15 instead of the last mentioned .514dth., for we have 52.15 for the multiplier 
of 1,712,554, and the product is 893 times, instead of 900 as desired, and lastly, it 
becomes still nearer, viz. 905.9 times, by using the mean heat within doors or 52°.9 
as above. This will, I trust, be considered sufficiently near and satisfactory. (N.B. 
It is equal to the quotient ef (95.000000),? x (572,360)? x by 753%). 
Afer the above was written, I found in the lst volume of the Gleanings of 
Science, page 96, that Mr. Prrnsep has noticed the little reliance which is to be 
placed on WepGwoop’s Pyrometer, the degrees of which I have used in the former 
calculations: this will not, however, affect the answer last given, viz. 905.9 where 
Ihave quoted that gentleman’s own experiment, so that the statement is left 
nearly as I had at first written it; but as the measure of temperature, of some of 
the metals there shewn, differs considerably from the corresponding ones here 
noted, it is right to state, that in that work the metals are represented to melt, 
at the undermentioned degrees of heat : 
47779 F. or its equivalent of WrpGwoop. 
Sil t DOSS. sms ae 0: DANIEL. 
so iallge TSSOO Fo. Soe cc endo: PRINSEP. 
TS22R7 Bs elses wer Oe 
G@eld’at 11° 2822.6. 01.3... do. } Monveav. 
The degree of heat of the comet above fusing silver, &c. will therefore be as 
follows, taking 100° for owr temperature : 
2,755,500 + 4,777 = 576 times using WEeDG-)] 
For melting Sil- woop’s |  atalie 
ver, 2,755,500 — 2,233 1,234 .. do. Dantex’s > euate. 
2,755,500 —~ 1,380 = 1,595... do. Prrnsep’s | 
[2,755,500 — 1,822. 611 do. UMonveav's 
: : rature. 
For Gold. 1 2,755,500 = 2,517.6 1,094 do. 
Correction. 
Instead of 2,755,500 as a numerator, on the assumption of 100° being the heat 
on the earth, take the medium heat, as before, 52°.15, and the quotient of 
95,000,000? — 572,300? ==or 1,436.990, and divide it by the degrees of the metal, 
thus ; 
Than silver fusing, the comet is 308 times hotter, by using WEDGwoop's degrees 
4,777, 
Do. 1.436,990+2,233 = 6434 times by DanreL’s Do. 
Do. 1,436,990+1,830 = 785°-———— Prinser’s Do. 
Do. 1,436,990—1,822.7 — 788° 
Gold...... .- 1,436,990—2,517.6 == 570° 
} Monveav’s Do. 
