History and Work of the Warner Observatory, Rochester, N. Y. 1883-1886, Vol. 1 (Classic Reprint)
| Preis: | 10.95 EUR* (inkl. MWST zzgl. Versand - Preis kann jetzt höher sein!) |
| Versand: | 0.00 EUR Versandkostenfrei innerhalb von Deutschland |
| Partner: | buecher.de |
| Hersteller: | Forgotten Books (Rochester, Rochester) |
| Stand: | 2015-08-04 03:50:33 |
Produktbeschreibung
Excerpt from History and Work of the Warner Observatory, Rochester, N. Y. 1883-1886, Vol. 1 Another prevalent error that has obtained is that powerful steam or gas motors are necessary to rotate them. To revolve the Warner dome, pulling or pushing-depending on the direction desired - on a perpendicular arm of tough oak, attached to the ring is all that is required, and this simple and inexpensive device is sufficient also for a dome forty feet iu diameter, if properly made. I have seen this dome completely revolved by the band of a boy of seventeen in 47 seoonds, and, pulling with the middle anger of one hand, in 70 second. The only drawback to this ease of movement is its rotation, when the shutter is open, by the winds, which, however, is remedied by a simple device. Iu constructing a dome one esseutial is not to be overlooked, viz: the width of the ring or solo-platc, as it is this rather than its ribs that constitutes its sinews, as no matter how strongly It may be ribbed, the ring, after the wear of a few years, is liable to become elliptical, and therefore Inoperative beyond restoration. Our ring Is composed of two thicknesses of 1 3-4 Inch pine joined together with white lead paint (instead of glue and well bolted and spiked together. On the under side is bolted another thickness of the pine, though only as wide as the distance apart of the car-wheels, or about eight inches, which leaves on either side the upper portion projecting over the lower. Each of the upper layers are 15 Inches wide. To both Inner and outer edges of this narrow under-strip steel wagon tire Is bolted with ooacb screws, the former being two, aud the latter two and a quarter lnohea wldo, and 5-16 of an inch thick. Those form the upper tracks, whose edges rest on the faces of the wheels. It must be borne in mind that the steel tracks largely provent sagging of the ring between the wheels. The wall-plate Is the exact counterpart of the ring, save that the narrow strip Is at the top. The wheels, which are ten inches in diameter (and should have been fifteen), are flanged like oar wheels, and are attached, one on each end of a short Bbaft. As I feared the machinist would fail to secure the exact relative proportions iu size, the wheels were left loose on the shaft aud may revolve if necessary. The pairs are not tied together, as it involves a useless expense not only, but also an increase of friction. Twel vepairs were at first used, but woresoou reduced to eight. The dome is covered with galvanized iron, formed to fit the ribs, and riveted at the angles, as shown in fig. 1. The lower sheet is strongly nailed to the outer edge of the ring, and render* sagglug between the wheels an impossibility. As in every direction the dome is an arch, and greatly stiffened by the angle, the ribs, except the two main ones, after the completion of the doineare of little use, save in the upper portions where they About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
* Preis kann jetzt höher sein. Den aktuellen Stand und Informationen zu den Versandkosten finden sie auf der Homepage unseres Partners.
Folgende Produkte könnten dir ebenso gefallen
