M. MELLONI ON LIGHT AND RADIANT HEAT. 237 
Seine after heavy rains. As the bore of this 
Avell proceeded, several lots of very minute 
eels floated out from it : many of them were 
caught alive and sent to Paris. A M. Dieu 
has lately announced to the French academy, 
that he is occupied in endeavouring to use 
steam-power as an agent in this art. 
In a well lately bored in one of the abattoirs 
(public slaughter-houses) of Paris, the depths 
and thicknesses of the strata were carefully 
noted ; and M. Arago himself examined the 
temperature of the water obtained : at 815 feet 
deep, he found it to be 68|^ Fahr. The en- 
gineer was prepared to have gone down to 
1300* feet, but having pierced through the bed 
of chalk under which was found the water at 
Elbeuf, he desisted at the depth of 815 feet. 
From this depth the water rose to within 16f 
feet of the surface. 
If now we look on the other side of the pic- 
ture, and regard the failures in France, we 
shall find a case the most remarkable for the 
extent of area over which unsuccessful at- 
tempts have been made, in the valley of the 
Garonne. From Toulouse to Bordeaux little 
hope is now entertained of profiting by wells 
of this kind. At Toulouse, the bore was car- 
ried down about 780 feet, being 282 feet below 
the level of the Mediterranean, and abandon- 
ed after a cost of above 1100/. At Agen, at 
the depth of 400 feet, a series of calcareous 
earths, &c., similar to what had already been 
passed, again commenced, and the undertaker 
gave it up in despair- In Bordeaux, they 
bored through strata, &c., very like w'hat had 
been met with at Toulouse, and not having met 
with water at 670 feet, it was deemed useless 
to proceed. Four other bores in the neighbour- 
ing department of La Gironde, were also un- 
successful ; in one only did water appear. 
These repeated failures have naturally in- 
disposed the inhabitants of this quarter of 
FTance to further attempts. A considerable 
addition to the geological knowledge of this 
part of the kingdom has, however, been 
obtained ; and among the facts collected by 
M. Boisgeraud, there is one result relating 
to the temperature of the earth, from 30 feet 
below the surface down to 340 feet, which 
deserves to be recorded. The mean of seven 
observations, each of twenty-four hours’ du- 
ration, was found to be2f° Fahr. for each lOO 
feet of depth ; an increase which accords with 
that which is generally admitted. 
The first bored well executed in the empire 
of Russia, was recently and successfully com- 
pleted at Riga. 
CURVILINEAR DIRECTION OF WINDS. 
Careful and continued observations, con- 
tained in the annual reports furnished by the 
several academies in the state of New York, 
to the Regents of the University, appear to 
demonstrate the fallacy of the notion common- 
ly entertained, that winds are generally rec- 
tilinear in their progress, and blow for the 
most part in right lines over extensive por- 
tions of the earth’s surface ; an error which 
appears to remain undisturbed in the minds 
of most meteorologists. 
TEMPERATURE OF CANTON AND 
MACAO. 
Mr. Meyen, for some time a resident at 
Canton and Macao, states as the result of his 
own observations, and those of other residents 
during very considerable periods, that the 
mean temperature of Canton is 71§8 Fahr. 
and that of Macao 721^^ Fahr. It will faci- 
litate accurate comparison to remark that the 
mean temperature of London, as stated by 
Professor Daniell, is 49§“ Fahr. 
FILTRATION AND COOLING OF LIGHT. 
M. Melloni, in examining the correctness 
of his opinion, that light and radiant heat 
were produced by different causes, and that 
there was therefore a possibility of separating 
them from each other when combined, has 
succeeded in accomplishing this remarkable 
experiment. By a process extremely simple, 
he separates light from radiant heat, whether 
proceeding from ordinary fires or from the sun. 
His mode is this : — The radiation from a lumi- 
nous body is passed through a system of dia- 
phanous bodies, — these absorb all the radiant 
heat, and extinguish but a very few of the 
luminous rays. The pure light emerging from 
such a system is found not to affect the most 
delicate thermoscope, even when concentrated 
by lenses to a brilliancy equal to that of solar 
light. The substances hitherto employed m 
tins heat-absorbing system, are water, and a 
peculiar kind of green glass, coloured by oxide 
of copper. The cooled and filtered light, 
as it may be termed, is decidedly yellow, 
with a tint of bluish-green, 
VARIATION OF TEMPERATURE IN 
ROCKY STRATA. 
Mr. W. Henwood conceives that he has 
satisfactorily ascertained that a difference of 
2 ^ — 3^ Fahr. exists in the temperature of the 
schistose and granitic strata of Cornwall, when 
they are severally examined at the same depth. 
It is not stated to which the higher tempera- 
ture belongs. 
REFLECTED HEAT MEASURED. 
The fact that heat is reflected more or less 
abundantly in proportion to the nature and 
polish of the surface upon which it impinges. 
Wots confirmed by the researches of Rumford 
and Leslie; but these philosophers did not pro- 
ceed to ascertain the proportion, in each par- 
ticular case, of the incident, to the reflected 
heift. It is easy to imagine a variety of cases, 
in ivhich, the property of the reflection of heat 
being known, and also that its quantity was 
variable, it would be desirable, and often ex- 
ceedingly useful, to be able to ascertain the 
amount which could be obtained from any 
particular body and surface. M. Melloni 
has recently shown, that by means of an ap- 
paratus, designed by him, the problem can be 
solved with great accuracy. Another instance 
in which the genius of M, Melloni, aided by 
the exquisite delicacy and sensibility of his 
apparatus, has detected and exhibited proper- 
ties and proportions of this invisible and uni- 
versal agent, which appeared a short time ago 
to lie far beyond the utmost reach of the 
powers of man; 
