422 
THE MEDITERRANEAN NATURALIST 
award that the jury could give. Connoisseurs, 
savants and manufacturers were greatly interested 
in it, though it had not reached the degree of 
perfection to which it has been brought to-day. 
The great question, that which leads all others 
since the new invention tends to produce a revo- 
lution in one of the greatest of French industries 
is, can this discovery be utilised for the growing 
needs of the people? 
A complete answer in the affirmative has been 
given to-day by M. de Chardonnet, who has al- 
ready, by enlisting the sympliathies of several bus- 
iness men, built a mill at Besancon, where the 
“silk” is being manufactured. Raw material is 
made froom wood pulp, such as is used for the 
fabrication of certain kinds of paper. This pulp 
is carefully dried in an oven and plunged into a 
mixture of sulphuric and nitric acids, then washed 
in several water baths, and dried by alcohol. 
The product thus prepared is dissolved in ether 
and pure alcohol, and the result is collodion, simi- 
lar to that used in photography. This collodion 
which is sticky and viscous, is enclosed in a solid 
receptacle, furnished with a filter in the lower- 
end. An air pump sends compressed air into the 
receptacle, and by its pressure the collodion is 
passed through it horizontally. This tube is armed 
with 300 cocks, of which the spouts are made 
of glass, and pierced by a small hole in the 
diameter of the thread of a cocoon as it is spun 
by the silkworm. 
The spinner opens the cock, and the collodion 
issues m a thread of extreme delicacy (it takes 
six to make a thread of the necessary consistence 
for weaving). This thread is not, however, fit 
to be rolled on spools by reason of its viscosity 
and softness. The matter is yet as collodion, and 
not silk To produce the necessary hardness the 
inventor resorted to a very ingenious but simple 
method. The little glass tube already mentioned 
is surrounded by a small reservoir of the same 
material constantly filled with water; when the 
thread issues from the aperture in the manner 
described, it traverses this water, which takes up 
the ether and alcohol, and the collodion becomes 
solidified, that is to say, it is transformed into an 
elastic thread, as resisting and brilliant as ordi- 
nary silk. 
One more detail. On account of the materials 
employed in the manufacture of this silk — wood 
ether and alcohol — it might be rightly supposed 
as was mentioned in the former report, that the 
stuff manufactured would be dangerously inflam- 
mable. M. de Chardonnet has apparently obvia- 
ted such a contingency by plunging the spun 
thread in a solution of ammonia thus rendering 
it as slow combustion as any other material. 
Another practical difficulty to be remedied in 
the invention is the frequent snapping of the slen- 
der threads issuing from the cylinder by 
reason of unequal pressure. This makes it impos- 
sible to maintain a standard quality for the out- 
put, and, consequently there may be produced 
five pounds of excellent silk folllowed by five 
pounds of a comparatively worthless quality. This 
difficulty is being overcome, but until it is com- 
pletely removed men of large means will not in- 
vest largely in the stock of the company which 
has been formed to exploit Count Chardonnet’s 
invention. 
Up to the present time none of the rich and 
important silk men of St. Etienne and Lyons 
have invested heavily in this enterprise. They 
ail profess to believe in it, and declare that in a 
few years artificial silk produced by this process, 
when it shall have been somewhat improved in 
certain details, is destined to figure largely in the 
commercial world. 
The disposition to-day on the part of French 
capitalists is to await developments. When the 
process is once perfected, and its results are whol- 
ly satisfactory, there will be a lively struggle 
for the control of this valuable invention, and 
there seems to be no doubt of the ability of the 
inventor to remove every obstacle which stands 
in the way of perfect practical success. 
Sui Limacidi dell’ Algeria. 
Prof. C. POLLONERA. 
Sotto questo titolo comprendo i generi di mol- 
luschi terrestri nudi appartenenti alle famiglie 
Arionidce e Limacidcv. Da questTdtima fainiglia 
escludo il genere Parmacella , perche la conchiglia 
opercolata che esso possiede nel suo juimo studio 
di vita mi sembra indicare una provenienza abba- 
stanza diversa da quella dei veri Limacidi. 
