Meteorology. 163 
known author of the ‘‘ Book of the Farm”), in a letter to Professor Bal- 
four, remarks :—‘‘ When Noah's ark, or the boat, as it is called by the 
country people—I don’t know its scientific name—occurs, a fall is indi- 
eated. ‘The ark consists of a convergence of clouds towards a point on 
each side of the horizon, and the line between the points is always at 
right angles to the wind for the time being. When the clouds consist of 
the cirri, which they usually do, the fall will occur in twelve hours, snow 
in frost, and rain in summer. I had a confirmation of this result, which 
I never saw fail, while visiting Lord Wharncliffe this Christmas at Wort- 
ley, near Sheffield. The ark appeared distinctly in the heavens, with a 
clear sun, on Monday afternoon, and a heavy fall of snow took place on 
Tuesday, Christmas-day, and which I predicted firmly on the Monday. 
“¢ Another certain indication is, that when a severe thunder storm occurs 
in May or early in June, cold weather will follow for six weeks. This 
was verified to the letter this season. 
‘¢ Another indication is, that when a bright aurora borealis occurs in 
autumn, and for the first time in the season, a heavy rain and storm will 
be sure to come in forty-eight hours, and for two or three days together. 
This has been repeatedly verified by Dr Christison, from whom I ob- 
tained the information. 
‘‘T] may mention, that while at Wortley I placed the self-registering 
thermometer in the snow, a slight shower of which had fallen before I went 
to that part of the country, from where it usually stood in front of a large 
hedge of Portugal laurels, and it there showed a difference of 7° during 
the course of the twenty-four hours, and on Christmas morning it marked 
2° below zero, This shows how important it is to know the position of a 
thermometer before you can judge of its indications. 
“ From this circumstance, I am persuaded that the Marquis of Tweed- 
dale’s prizes for ascertaining the temperature as affecting the thermo- 
meter when exposed as the crops are, will reveal some curious and im- 
portant results; for to take the temperature constantly in the shade, is 
equivalent to taking it only in a cloudy day, in so far as the heat from 
the sun is concerned.—I am yours sincerely, Henry STEPHEN. 
On the Temperature of the Earth's Crust, as exhibited by Thermome- 
trical Observations obtained during the sinking of the Deep Mine at 
Dukinfield. By W. Fairpatrn, LL.D., &c.—During the prosecution 
of researches on the conductivity and fusion of various substances, an op- 
portunity occurred of ascertaining by direct experiments, under favour- 
able circumstances, the increase of temperature in the crust of the 
earth. This was obtained by means of thermometers placed in bore- 
holes, at various depths, during the sinking of one of the deepest mines 
in England, namely, the coal mine belonging to F. D. Astley, Esq., at 
Dukinfield, which has been sunk to a depth of 700 yards. The increase 
of temperature in descending, shown by these observations, is irregular ; 
nor is this to be wondered at, if we consider the difficulties of the en- 
quiry, and the sources of error in assuming the temperature in a single 
bore-hole as the mean temperature of the stratum. At the same time, 
it is not probable that the temperature in the mine-shaft influenced the 
results. The rate of increase has been shown in previous experiments to 
be directly as the depth, and this is confirmed by the experiments. The 
amount of increase is from 51° F. to 572°, as the depth increases from 
53 to 231 yards, or 1° in 99 feet; but, in this case, the higher tempera- 
ture is not very accurately determined. From 231 to 685 yards, the tem- 
perature increases from 572° F. to 753°. This is a mean increase of 1° in 
76°8 feet, which does not widely differ from the results of other observers. 
Walferdin and Arago found an increase of 1° in 59 feet; at Rehme, in 
an Artesian well 760 yards deep, the increase was 1° in 54°7 feet; De 
La Rive and Marcet found an increase of 1° in 51 feet at Geneva. 
