7% 
~ This agrolite must therefore be of a 
different species from those that have 
hitherto been analysed, since it con- 
tains neither magnesia nor chrome, sub- 
. Stanices constantly: found in other stones 
of this description; and in containing a 
considerable quantity of alumine, traces 
only of which have bee discovered in 
others. 
The primitive form of the diamend, i 
known to be a regular octaedron. Most 
frequently it presents itself in spheroidal 
crystals, or with curvilinear facets, It 
has been found cubical, plano-convex, 
eylindroid; but it was not suspected to 
be susceptible of that variety of form, 
which Romé de VIsle termed macée, and 
Hatiy has named hemitrope, that is, where 
half of the crystal is turned back, so as 
to form re-entering angles, as is seen in 
some varieties of the ruby, feldspar, &c. 
Among the rough diamonds, however, 
given by M. d’Arcet, to Messrs. Guyton 
Morveau, Hachette, and Clement, for a 
series of experiments on their combus- 
tion ; 
thought proper to set aside as presenting 
the first example of such a structure. It 
weighs nearly eleven grains. The spe- 
cific gravity 193,512. It is formed of 
two demi-spheroids, the deflected posi- 
tion of which, imperfectly terminated at 
ene of the extremities, exhibits at the 
other the very decided re-entering angles 
that characterise the. hemitrope. 
The aqueducts constructing at Paris, 
’ have enabled M. Bror to make expe- 
riments on the propagation of sound, 
through solid bodies, on a larger scale 
than had hitherto been done. The total 
Jength of the pipes was, 3118 feet. -A 
blow with the hammer at one end, was 
heard at the other producing two distinct 
sounds; the interval of which measured 
in more than 200 trials was 2,5”. . The 
temperature was 11° (51,8 F.) Accord- 
ing to the experiments of the Academy, 
the time of the propagation of sound 
‘to this distance, through thé air, should 
be 2,79", at this temperature ; from 
which, if we deduct 2,5”, the interval 
observed, we have 0,29” for the time the 
sound was in being ih a through 
the solid substance. 
confirmed in another way. Two persons 
were stationed at the opposite extremities 
of the pipe, each provided with a half- 
“second watch, carefully compared, and 
each struck alternately with a hammer 
at intervals, of O 15580, and 45 seconds. 
The time of the arrival of the two sounds 
was noted, and the sum of the numbers 
\ Literary and Philosophical I ntelligence. 
- appears .to-confirm the results. 
there was one which those chemists © 
This result was 
‘[Beb. 5 
indicated by ‘the watches, gave double - 
the time of the propagation by the solid 
substance, independent of the difference 
there might be between them. Thusthe 
time of ‘the transmission by the solid, 
was found by repeated observations. to 
be 0.26", and of that by the air.2.76”. 
The first result differs from. that given by 
the intervals of the sounds only 0.03”; 
and the second diifers from the time de, 
duced from the observations of the aca- 
demy just as much; an agreement that 
M. Biot 
likewise observed that, at. this distance, 
the lowest voice might be heard perfectly 
well from one end to the other, and with 
sufficient | distinctness to keep oP a con- 
versation. 
M. Lescuzyry, chief commissary of 
gun-powder and saltpetre, has sent from 
Dijon, to the Council of Mines, a collec- 
tion of specimens.of rocks, interesting on 
account of the green particles which they 
contain, Several pieces of this stone, 
and a_ siliceous breccia, improperly 
called chalcedony of Creuzot, containing 
the same substance, had been found in 
abundance on the road, and Messrs. 
Guyton and Le Lievre, had ascertained 
that the green colour was not owing to 
copper: but it was not known whence 
they came. After much search, M. 
Leschevin discovered these green rocks, 
in three contiguous mountains, and found 
that they were colored by oxide of 
chrome, combined in greater or Jess 
quantity with silex, alumine, &c. On 
oné of those mountains he met with the 
graphic granite, which several authogs 
have mentioned as accompanying the 
emerald; and he intends to search for 
that stone also, which M. Vauquelin has 
discovered to be sometimes coloured 
with chrome. Since M. Dreppier has 
shown, that chrome united with lead, 
makes the most beautiful of yellows, this 
discovery may prove of considerable ad- 
vantage. 
EAST INDIES. 
A shark of extraordinary earns 
some months since made its appearance 
in the upper parts of the river Hoogley, 
where the Hindovos are accustomed to 
perform their ablutions. Many attempts 
were made to destroy it but in vain. 
Three bramins with several of their fol- 
lowers were among its victims, and the 
greatest consternation prevailed- among 
the bathers, who rather than forego a 
“practice consecrated by their religion, 
were content to enjoy it at the ack of 
their liv C56 
AMERIGAs 
ideal 
