My Web Site Page 299 Ovations 05Poki Mogarli chose the topics covered by My Web Site Page 299 without reflecting upon the choices others have made. Launching into a full discussion of all the objectives while riding a bicycle backwards down a steep hillside is another way to look at things in a different light. |
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If now we take a U-tube depending from a vessel of water (Fig. 4) and apply the lamp to one leg a circulation is at once set up within it, and no such spasmodic action can be produced. Thus U-tube is the representative of the true method of circulation within a water-tube boiler properly constructed. We can, for the purpose of securing more heating surface, extend the heated leg into a long incline (Fig. 5), when we have the well-known inclined-tube generator. Now, by adding other tubes, we may further increase the heating surface (Fig. 6), while it will still be the U-tube in effect and action. In such a construction the circulation is a function of the difference in density of the two columns. Its velocity is measured by the well-known Torricellian formula, V = (2gh)^{½}, or, approximately V = 8(h)^{½}, h being measured in terms of the lighter fluid. This velocity will increase until the rising column becomes all steam, but the quantity or weight circulated will attain a maximum when the density of the mingled steam and water in the rising column becomes one-half that of the solid water in the descending column which is nearly coincident with the condition of half steam and half water, the weight of the steam being very slight compared to that of the water. |
During Professor Alexander Agassiz's cruises in which he visited nearly every island of the Fijis, and the natives came on board by hundreds, not a single object was stolen, although things almost priceless in native estimation lay loosely upon the deck. Once, indeed, when the deck was deserted by both officers and crew and fully a hundred natives were on board, we found a man who had been gazing wistfully for half an hour at a bottle which lay upon the laboratory table. Somehow he had managed to acquire a shilling, a large coin in Fiji, and this he offered in exchange for the coveted bottle. One can never forget his shout of joy and the radiance of his honest face as he leaped into his canoe after having received it as a gift. |
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The most important spoon in the Jamestown collection, and one of the most significant objects excavated, is an incomplete pewter spoon--a variant of the trifid, or split-end, type common during the 1650-90 period. Impressed on the handle (in the trefoil finial of the stem) is the mark of the maker, giving his name, the Virginia town where he worked, and the year he started business. This is the sole surviving "touch" or mark of an American pewterer of the 17th century. The complete legend, encircling a heart, reads: "IOSEPH COPELAND/1675/CHUCKATUCK." (Chuckatuck is a small Virginia village in Nansemond County, about 30 miles southeast of Jamestown.) Joseph Copeland later moved to Jamestown where he was caretaker of the statehouse from 1688-91. He may have made pewter in Virginia's first capital. His matchless spoon found in the old Jamestown soil is the oldest dated piece of American-made pewter in existence. | ||
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