Scientific American Supplement No. 822, October 3, 1891 eBook

This eBook from the Gutenberg Project consists of approximately 128 pages of information about Scientific American Supplement No. 822, October 3, 1891.
the back of an aphide with its antennae to coax it to give down its sweet fluid, much in the same way as a dairy maid would induce a cow to give down its milk by a gentle manipulation of its udders.  Some species, principally the masons and miners, remove their aphides to plants in the immediate vicinity of their nest, or even introduce them into the ant home.  In the interior of most nests is also found the small blind beetle (Claviger) glistening, and of a uniform red, its mouth of so singular a conformation that it is incapable of feeding itself.  The ants carefully feed these poor dependent creatures, and in turn lick the sweet liquid which they secrete and exude.  These little Coleoptera are only found in the nests of some species; when introduced into the nests of others they excite great bewilderment, and, after having been carefully turned over and examined, are killed in a short time as a useless commodity.  Another active species of Coleoptera, of the family Staphylini, is also found in ant nests.  I have discovered one in the nest of Formica rufa in the Jewish cemetery in Leadville.  Furnished with wings, it does not remain in the nest, but is forced to return thither by the strange incapacity to feed itself.  Like the Claviger, it repays its kind nurses by the sweet liquid it exudes, and which is retained by a tuft of hair on either side of the abdomen beneath the wings, which the creature lifts in order that the ant may get at its honeyed recompense.  Such mutual services between creatures in no way allied is a most curious fact in the animal world.—­Popular Science News.

* * * * *

A GEM-BEARING GRANITE VEIN IN WESTERN CONNECTICUT.

By L.P.  GRATACAP.

In the county of Litchfield, Conn., in the midst of some of the most attractive hill country of that region, a very striking mineral fissure has been opened by Mr. S.L.  Wilson, which, in both its scientific and commercial aspects, is equally important and interesting.  It is a broad crevice, widened at the point of excavation into something like a pocket and filled, between its inclosing walls of gneiss, with a granitic mass whose elements have crystallized separately, so that an almost complete mineralogical separation has been effected of quartz, mica, and feldspar, while associated aggregates, as beryl and garnet, have formed under conditions that make them valuable gem fabrics.

The vein has a strike south of west and north of east and a distinct dip northwest, by which it is brought below the gneiss rock, which forms an overhanging wall, on the northerly side of the granitic mass, while on the southerly edge the same gneiss rock makes an almost vertical foot wall, and exhibits a sharp surface of demarkation and contact.  The rock has been worked as an open cut through short lateral “plunges,” or tunnels have been used for

Copyrights
Project Gutenberg
Scientific American Supplement No. 822, October 3, 1891 from Project Gutenberg. Public domain.
Follow Us on Facebook