The presence of foreign substances in the
silk, is fatal to proper dyeing; hence the
dyer proceeds to get rid of them by means of
boiling the silk in soap and water. As silk
thread becomes charged with foreign matters
to various degrees, given weights of several
samples will contain very different lengths.
In this way manufacturers are often deceived
in the produce of various parcels of thrown
silks after coming from the loom.

In our own country, great as have been the
strides made by most branches of
manufacture, the silk spinner or weaver has
quietly borne all these evils and disappointments
in deepest ignorance of the Chemistry
of Silk, and perhaps believing that "Where
ignorance is bliss, 'tis folly to be wise." He,
alone, of all the workers, has neglected to
seek the friendly aid of the chemist.

Possibly it is this indifference to science,
which has left the silk manufacturer so far
behind every other son of industry. It is
notorious that, whilst our cotton, linen, and
woollen manufactories have been multiplied
ten-fold during the last score of years, those
of silk goods have made scarcely any progress.
The manufacturers are themselves perfectly
aware of this startling fact, and it was but a
few months since that a memorial was
presented from them to the legislature, praying
that all remaining protection on their goods
might be removed, as the only hope of giving
a new vitality to their slumbering trade.

The truth is, that Frenchmen are more
keenly alive to the value of science in
connection with manufacture than ourselves.
Whilst our silk manufacturers have gone on
upon the old well-beaten track, those of
France have enlisted in their behalf the
services of the chemist, who has brought their
raw material as completely under his analytical
control as subtle gas or ponderous ore.
He has demonstrated to a nicety that its
relative purity, its strength, its elasticity, its
durability, its structure, the very size and
weight of each separate fibre, may be shown
and registered with precision and certainty.
He tells the manufacturer the actual amount
of latent moisture contained in a pound of
silk; he shows him how much natural gum,
resin, and sugar, every bale comprises: he
points out how much lighter his thread should
be after the processes of spinning and dyeing;
and, more valuable still, he indicates the most
profitable use to which every bale of raw silk
is applicable: that whilst one parcel is best
adapted for the manufacture of satin, another
may be better employed for plain silk, another
for velvet, and so on to the end.

In France, Italy, and other parts of
continental Europe, the assaying, or, as it is
there technically termed, the "conditioning of
silk," is carried on under the sanction of the
municipal authorities, in establishments called
Conditioning Houses. The quantity thus
assayed is published weekly for the information
of the trade with as much regularity as
a Price Current. In this way we may find
it publicly notified that, in the Conditioning
House at Lyons there were during last
year five millions, thirty-seven thousand, six
hundred and twenty-eight pounds of silk
assayed; at Milan, three millions, four hundred
and sixty-six thousand, six hundred and
ninety-one pounds, and other large quantities
at St. Etienne, Turin, Zurich, Elberfeld, and
other places.

Of so much importance has this process
been deemed in France that, in 1841, a royal
ordonnance was passed, setting forth the
ascertained weight which silk loses by the
conditioning process, and which is eleven
per cent. This eleven per cent., added to the
weight of the silk after the ordeal it has gone
through, makes up what is termed its
merchantable weight.

The French have brought to our doors the
means of accomplishing what they have
practised during the last twenty years, with so
much advantage. These means are no
further removed from us than Broad Street
Buildings, in the City, in premises lately
occupied by one of the many Colonial bubble
Companies which have so multiplied during
the past half century. Science has established
herself where humbug so recently sat
enthroned.

We have paid a visit to these premises.
The first operation we beheld was that of
determining the humidity of silk. Eleven per
cent, is the natural quantity in all silk, but
from various causes this is nearly always
much exceeded. Several samples of the
articles having been taken from a bale, they
are weighed in scales, capable of being turned
by half a grain. Two of these samples are
then placed in other scales, equally delicate
and true; one end of which, containing the
sample, being immersed in a copper cylinder
heated by steam to two hundred and thirty
degrees of Fahrenheit, the other, with the
weights, being enclosed within a glass case.
The effect of this hot-air bath is rapidly seen;
the silk soon throws off its moisture, becomes
lighter, and the scale with the weights begins
to sink. In this condition it is kept until no
further loss of weight is perceived;—the
weight which the silk is found to have lost
being the exact degree of its humidity. The
natural eleven per cent. of humidity being
allowed for, any loss beyond that shows the
degree of artificial moisture which the silk
contains.

To determine the amount of foreign matters
contained in a sample of silk, the parcels—after
a most mathematical weighing—are boiled
in soap and water, for several hours. They
are then conveyed to the hot-air chambers,
subjected to two hundred and thirty degrees
of heat, and finally weighed. It will be found
now that silk of the greatest purity has
lost not only its eleven per cent. of moisture,
but a further twenty-four per cent. in the
various foreign matters boiled out of it. But