196 
five’ francs, upon common paper. In an 
economical point of view, this process de- 
serves to be recommended.-—-Bulletin Uni- 
versel. 
New Division of the Thermometer. —Lieu- 
tenant Skene, who accompanied Captain 
Parry in his expedition of 1820, has re- 
newed the idea of dividing the thermometric 
scale according to the fusion of two solid 
bodies, and not according to the fusion and 
vaporization of one, as hitherto hes been 
done. In truth, the circumstances proper 
to give a fixed degree of temperature by 
the vaporization of a liquid cannot be 
united at will, while the fusion of a solid 
body to a liquid state is determined only 
by the affinity of the particles of the body 
for each other and for caloric, and depends 
upon no other cause. Mr. Skene proposes 
to establish as the thermometric unity, the 
difference of temperature between the de- 
gree at which mercury fuses, and that at 
which ice melts, care being taken that 
these two substances are perfectly pure. 
This unity is to be called a degree, and to 
be divided into 100 minutes. The point 
at which ice melts would, as at present, se- 
parate the cold from the heat, and be 
marked 0. ‘The ascending minutes would 
have the sign +, the descending ones the 
sign —. An advantage would result by 
the highest temperatures, even those at 
which the least fusible metals are melted, 
being denoted by low numbers. Between 
the melting of ice and the boiling of water 
there would not be more than about 2° 50’; 
zine would melt at 9°, &c.: numbers more 
easily to be remembered than those at pre- 
sent employed. The graduation of ther- 
mometers would certainly be more difficult, 
and could only be entrusted to skilful 
artists: this, however, would be of the 
greatest benefit, fully appreciable, indeed, 
only by those who have felt to what a de- 
gree the scientific world is infested with 
- thermometers on which not the slightest 
reliance can be placed. 
Depth of the American Lakes.—Lake 
Ivie has about thirty-five fathoms of water 
above its lowest bed, though it is not often 
more than twenty-five indepth. Lake St. 
Clair is shallow, rarely exceeding four 
fathoms. Lakes Huron, Michigan, and 
Superior are in places 900 feet deep, sink- 
ing about 300 feet below the level of the 
ocean. — Silliman’s Journal. 
Spontaneous Combustion of Chlorine and 
Olefiant Gas.—It has long been known that 
chlorine and hydrogen in mixture are liable 
to explode when struck by the direct rays 
of the sun. But we believe the first ac- 
count of a similar action on the part of 
chlorine and olefiant, or heavy carburetted 
hydrogen, is related by Professor Silliman 
in the last number of his American Jour- 
nal. It is well known that these bodies, 
when mingled in about equal volumes, com- 
bine. quietly, and become condensed into 
the peculiar aromatic oily-looking sub- 
Philosophical, Cheniical, and Scientefic Miscellanies. 
[Ave. 
stance since called chloric ether. “ ‘This’ ef- 
fect,” he says, “ Ihad so often Avitnessed, 
and had never seen any material variation 
in the result, that I was not prepared to 
look for any thing else. But in an ex- 
periment of this kind, January 5, 1826, 
happening to mingle the chlorine with the 
olefiant gas in such a manner that the latter 
gas was uppermost, the combination went 
on more slowly than when the reverse 
order was observed, and the oily matter 
was gradually precipitated, but was less 
abundant in quantity than usual; and re- 
peating the experiment in the same manner, 
the gases had remained in contact a few 
minutes, apparently without mingling much 
except at their surfaces, the chlorine pre- 
serving its peculiar colour, and the other 
gas its colourless transparency, when sud- 
denly a bright flash pervaded the bell glass, 
which was of the capacity of five or six 
quarts; it was raised out of the water with 
aslight report; a dense deposit of charcoal 
lined the glass and floated on the water of 
the cistern, and the chlorine disappeared. 
The appearances were much like those 
which are exhibited when a rag dipped in 
oil of turpentine is placed in a jar of 
chlorine gas. Reflecting on the circum- 
stances, I was Jed to believe that the pe- 
culiar effect in this case arose from the fact 
that, owing to the great difference in the 
specific gravity of the two gases, the action 
took place principally at the two surfaces 
of contact; and thus the chlorine acting 
upon a comparatively thin stratum of in- 
flammable gas, the two became so heated 
as to pass into vivid combustion. Every 
new occurrence in practical chemistry 
which may involve danger ought to be 
exactly stated, that we may be aware of 
contingencies not otherwise anticipated.” 
Canal from Puris to Havre.—It is a fa~ 
yourite object with the present King of 
France to establish a navigable commu- 
nication between Paris and the sea, and 
a proposal has been made to construct a 
canal on the right bank of the Seine from 
Havre to Gauville, to follow the bed of 
the river from Gauville to Rouen, merely 
cutting off at Yainville a considerable angle, 
and from Rouen to Paris to run a eanal, 
on whichever side of the river may be 
most convenient, and crossing the river 
each time above the dams employed at 
present to regulate the depth of water. 
The proposed canals to be 65°618: feet 
broad at the bottom, 144°36 at the top, 
and 19°685 feet deep. These dimensions 
would allow not only large merchant-ships, 
but frigates of 18-guns, to come up to the 
French capital. The distance from Paris 
to Havre, which at present is 229°91 miles, 
would by this plan be reduced to Jess than 
180°2. The total expense is estimated, at 
10,458,333 pounds sterling. A plan has. 
likewise been proposed for establishing a rail ; 
road between Paris and Havre. At present 
thirty-five days are required for the trans- — 
