Scientific American Supplement, No. 711, August 17, 1889Various
History
Scientific American Supplement, No. 711, August 17, 1889
Various
Science -- Periodicals
It would be difficult for us to pass any judgment whatever upon the
musical and artistic value of these transmissions of trumpet music to
a distance; we prefer to confess our incompetency in the matter. But
it is none the less certain that these experiments are having the same
success that they had at their inception in 1881 at the Universal
Exposition of Electricity, and they allow us to foresee that there is
a time coming in which it will be possible to transmit speech to a
distance with the same intensity that the present trumpet flourishes
have. Although all the tentatives hitherto made in this direction have
not given very brilliant results, we must not despair of attaining the
end some day or other. Less than fifteen years ago the telephone did
not exist; now it covers the world with its lines.--_La Nature._
[Illustration: Fig. 4.--DETAILS OF THE RECEIVER.]
* * * * *
NOTES ON DYEWOOD EXTRACTS AND SIMILAR PREPARATIONS.
By LOUIS SIEBOLD, F.I.C., F.C.S.
During the last ten years there has been an enormous increase in the
production of these preparations, and the time will come when their
application in dyeing and calico printing will become so general as to
completely supersede the employment of the raw materials. The
manufacture of these extracts, to be thoroughly successful, requires
to be so conducted as to secure the perfect exhaustion of the dyewoods
without the slightest destruction or deterioration of the coloring
matters contained in them; and though nothing like perfection has been
reached in the attainment of these objects, it is certain that the
processes of extraction and evaporation now employed by the best
makers are a very great improvement on the older methods. Indeed,
there is no difficulty nowadays in procuring dyewood extracts of high
excellence if the consumer is willing to pay a price for them
corresponding to their quality, and knows how to avail himself of the
aid of chemical skill to control his purchases. Unfortunately,
however, there is so much hankering after cheap articles, and so
little care is taken to ascertain their real quality, that every scope
is afforded to the malpractices of the adulterer. There are many dye
and print works in which large quantities of these extracts are used
without being subjected to trustworthy tests. Moreover, much of the
testing is done by fallacious methods and often by biased hands. So
fallacious, indeed, are some of these tests, that grossly adulterated
extracts are often declared superior to the purer ones, the cause of
this being the application of an insufficient proportion of mordant in
the dyeing or printing trials, and the consequent waste of the excess
of coloring matter in the case of the purer preparation.
Public-domain text, read in full here on John Shaqi.
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