Page:Popular Science Monthly Volume 4.djvu/461

Rh now about to speak, the Columbite, on account of the derivation of its name and the history of its discovery. The rare metallic element columbium, or niobium as it has subsequently been called, was first discovered in 1802, by Hatchett, in a specimen of this mineral sent out by Governor Winthrop, of Connecticut, to Sir Hans Sloane, then president of the Royal Society, and the original analysis was made by Wollaston, with an accuracy truly surprising, upon only four grains of the specimen, so long ago as the year 1809. It is highly probable that Governor Winthrop's mineral came from Middletown, Connecticut, at which locality some very large crystals have since been found; among many such in the Spang collection, there is one composed of twenty-five crystals compounded together, and showing the terminal planes at the summit of each crystal. Two of the prismatic faces of one of these crystals are three inches in length.

There is a genus of minerals termed zeolites, from a Greek word signifying to boil, for the reason that when heated the large percentage of water which they contain escapes with intumescence, and of these one of the most remarkable species is scolecite, so called because, on touching it with the tip of a blow-pipe flame, it curls up like a worm. I find elsewhere the record of some crystals, which were found in the Berufiord, Iceland; and which exceeded two inches in length and were a quarter of an inch thick. There is a radiated mass of scolecite crystals in this collection, brought from Poonah, Hindostan, the largest being three inches in length, and compounded of two twins, each of which is one-quarter of an inch in diameter. The beauty of this group is still further enhanced by clusters of transparent tabular apophyllites attached to the sides of the crystals.

There is another species of zeolite, which, on account of its brilliant, pearly lustre, has received the name of stilbite. Usually its color is white; in this collection there is a specimen of stilbite from Poonah, that is compounded of a great number of individual crystals, the terminations of which together make up an octahedral summit with planes two inches wide. The color is a deep, rich salmon.

Of the apophyllites from the same locality, one of the most beautiful is a tabular square prism with the angles replaced by octahedral planes, all of which are perfect in lustre and surface polish. The crystal measures two and a quarter inches across, and is one and a quarter inch in height. There are remarkable suites of pink apophyllites from the Hartz, transparent green crystals, highly modified, from Nova Scotia, and some of the finest of those crystals which made the Erie tunnel through the trap-rock of Bergen Hill, New Jersey, at one time so famous among mineralogists. It is from such wonderful works as these that we are enabled justly to appreciate the transcendent skill with which Nature performs her task when she tries her hand at the plastic arts; for example, what piece of statuary could be so faultless, in grouping and finish, as one of these specimens,