New Heliometer.—Antiques.—Earthquake. 463 
sure, and indefinitely, the effect of the property of double re- 
fraction in those crystallized substances which present this in- 
comprehensible phenomenon. ! 
« We are indebted to the late M. Malus for an entirely new 
process for discovering in substances, whatever may be the al- 
teration from their primitive form, their axis of crystallization. 
The instrument which he contrived for this purpose is so in- 
genious, that it ought to be engraved on his tomb, like the cy- 
linder inserted within the sphere, which enabled Cicero to dis- 
cover the tomb of Archimedes in Sicily. It is best for the mea- 
surement of the sun, which we know to be about 32 minutes, to 
employ in my heliometer three or four cubes, shaped as I have 
deseribed, in order that this micrometer may be very close to 
the focus of the eye-glass, without altering in a sensible manner 
the goodness of the object-glass, and its dimensions not exceed- 
ing that of the diameter of the eye-glass. The importance to 
astronomy of the precise measurement of the diameter of the 
sun made me desirous that my colleague Arago should verify 
the heliometers which I sent to the Royal Observatory. This 
eminent astronomer has already verified, by numerous observa- 
tions, the diameter of the' principal planets by the microscope, 
on which the heliometer which I have now described is abso- 
Jutely calculated.” 
Mr. Sowerby is making a sword of meteoric iron, to present 
to the Emperor of Russia. 
"A very interesting discovery of ancient medals has been re- 
cently made in the department of Jura, in the Alps. A boy who 
was feeding sheep having ascended a very high rock, struck his 
stick against it, when to his surprise it entered easily. Having 
called the attention of some of his companions to the circum- 
stance, they dug into the aperture, and discovered a pot half zinc 
and half copper of the capacity of about two pints. It was 
filled with copper medals edged with silver, bearing the effigies of 
various emperors, of exeellent workmanship. Several have le- 
gends and exergues of various kinds, and all were covered with 
verdigrise. They are of the reign of Dioclesian, Constantine, 
Maximinus, &c. The form of the pot which contained these 
medals is antique: it is' contracted greatly at the upper part, its 
colour is whitish, but it exhibits neither inscriptions nor en- 
gravings. 
On the 22d of May, at half past 11 A. M.,. a shock of an 
earthquake was perceived at Oleron, in the South of France. 
| & Never,” says an eyewitness, “in the memory of the oldest in- 
habitants 
