178 Miscellaneous Intelligence. 
the shell for two ‘or three months, and then on a sudden be- 
comes white; shortly the spots and colours of the skin appear, 
and the insect ultimately passes into its perfect state, when it de~ 
posits its eggs. All these changes take place within the shell, and 
it is difficult to ascertain them without disturbing the animal and 
deranging the results. 
Drawings of the animal having been shewn to MM.La Freille and 
Audouin, they are inclined to believe that the insect in its perfect 
state is not merely a new genus, but a particular family, which 
they would place in the order of Thysanours, or in that of para- 
sites:— Bib. Univ. xxiv. 137. 
4. Hatching Fish—The Chinese have a method of hatching the 
spawn of fish, and thus protecting it from those accidents which 
ordinarily destroy so large a portion of it, The fishermen collect | 
with care on the margin and surface of waters all those gelatinous 
masses which contain the spawn of fish; after they have found a 
sufficient quantity they fill with it the shell of a fresh hen’s egg, 
which they have previously emptied, stop up the hole, and put it 
under a sitting fowl. At the expiration of a certain number of 
days they break the shell in water warmed by the sun, the young 
fry are presently hatched, and are kept in pure fresh water till they 
are large enough to be thrown into the pond with the old fish. The 
sale o spawn for this purpose forms an important branch of trade 
in China. 
5. Natural Changes in Carrara Marble.—Carrara marble pre- 
sents, according to M. Ripetti, an instance of chemical changes 
in the colouring principles without any alteration in the carbonate 
of lime. The marble of Carrara does not always possess that 
brilliant whiteness for which it is so famed; it is for the most part 
of a greyish tint, and is of its utmost whiteness only in certain . 
parts where veins have been formed, or else spots of oxide, sul- 
phate, or sulphuret of iron. Some of these stains are old and 
fixed, but others seem to be of recent formation and are removed 
by water running over them, so that ina short time the marble be- 
comes as white as snow. ‘The workmen express this effect by say- 
ing, ‘ The marble cleanses itself.” Whole masses seem to change 
by a chemical process, and in support of this opinion, it has been 
observed that the marble of the ancient excavation of St. Silvestro, 
which was formerly of no value, has now become excessively white : 
and that in general the different species of Carrara marble vary 
with time, and become more and more pure.—Gior. de Fisica. 
6. Note on the existence of a Nitrate and a Salt of Potash in 
Cheltenham Water, by M. Faraday, Sc.—Having undertaken at the 
request of Dr, Creaser an examination of some water from Chelten- 
