Scientific American Supplement, No. 315, January 14, 1882 eBook

This eBook from the Gutenberg Project consists of approximately 112 pages of information about Scientific American Supplement, No. 315, January 14, 1882.

The presence of starch glucose in sugar-house molasses may also be detected by the copper test.  The possibility of applying this test, as well as those already indicated, rests on the fact that starch glucose is always added in very large quantities for the purposes of adulteration.  A very small addition could not be satisfactorily detected.

The detection by the copper test rests on the observation that very nearly one-half of the soluble impurities in sugar-house molasses consists of glucose in the shape of inverted sugar.  We have seen above that for a molasses of 40 deg.  B. the soluble impurities amount to about 371/2 per cent.  We may, then, lay down the rule:  that the percentage of glucose shown by the copper test cannot, in a straight sugar-house molasses, be much greater than one-half of the number expressing the density in Baume degrees.  The reason is obvious from what has been said of the test by the optical saccharometer.

* * * * *

FALSE VERMILION.—­A curious case has been noticed in Germany, where a small cargo of vermilion was purchased, and, upon being analyzed, turned out to be red oxide of lead colored by eosine.  This is an entirely novel sophistication.  The eosine was separated from the oxide of lead by digesting the product for twenty-four hours in very strong alcohol.  A much shorter time is sufficient to color the spirit enough to enable an expert chemist to detect the presence of this splendid organic coloring matter.  Another kind of “vermilion” consists entirely of peroxide of iron, prepared especially to imitate the brilliant and costly sulphide of mercury, which it does very well, and is largely used in England, France, and America.

* * * * *



No body among the metals and the metalloids (silicium, titanium, tungsten, chromium, phosphorus, etc.) has occupied a more prominent position in modern metallurgy than manganese, and it is chiefly due to its great affinity for oxygen.  When this substance was discovered, more than a century ago (1774), by the celebrated Swedish chemist and mineralogist, Gahn, by treating the black oxide of manganese in the crucible, no one would have thought that the new element, so delicate by itself, without any direct industrial use, would become, in the middle of the nineteenth century, one of the most powerful and necessary instruments for the success of the Bessemer process, as well for its deoxidizing properties as for the qualities which it imparts to steel, increasing its resistance, its durability, and its elasticity, as has been shown elsewhere.

Project Gutenberg
Scientific American Supplement, No. 315, January 14, 1882 from Project Gutenberg. Public domain.
Follow Us on Facebook