Rensselaer Union, Volume 8, Number 11, Rensselaer, Jasper County, 2 December 1875 — MECHANICAL AND SCIENTIFIC. [ARTICLE]

MECHANICAL AND SCIENTIFIC.

—Hie ftivaffiigation made of the circumstanfles attending the wreck of the Ottawa ■on the Taranßti coast tends to confirm the ‘belief lopg since entertained by scientific men. that thd'magnetic iron sand, which there abounds in such immense quantities, is the cause of the steering compasses of ships and steamers running along shore in that region'becoming deranged. This has been alleged as the cause of the loss of the steamer Airdale, and some three or four other vessels. It will be remembered that some fifteen years ago many vessels were cast ashore on the South American coast, and, after many close investigations, it was discovered that the base of some of the mountains along the coast line contained large quantities of iron ore. —One of the recent improvements in the art of metallurgy meets a long-felt and important need, and will greatly facilitate and simplify some operations hitherto attended with much uncertainty. It.is well known that the difficulty of uniting iron to brass is created by the unequal rate of expansion in the two metals, which destroys the unity when the temperature is changed. To meet this obstacle, an English artisan has invented a peculiar kind of alltty, the expansion of which under the influence of heat is represented as peing so similar to that of iron and steel that the surface may be regarded when thus joined as permanently united lor all practical purposes. This alloy, as described, consists of three parts tft, thirty-one and a half parts copper and seven and a half parts zinc, and the variety of uses to which the material is adapted in metallurgical industry is of course quite large.— Scientific Exchange. —A new theory, now engaging the attention of astronomers, assumes that, at some distance below the sun’s surface, the pressure is of a character that substances —such as some metals—are in a liquid state, though at a temperature far exceeding their boiling point, under ordinary pressure. In this case the compressed liquids will, on the whole, arrange themselves in the order of density, and if the pressure be diminished, these will burst into vapor; the equilibrium is, therefore, unstable. Consequently it *is assumed that there may exist in the sun two or more liquids, so related that the deuser has the lower boiling point. If these disturbances of pressure occur, they will produce vertical eruptions through the upper layers of the sun, throwing up the chromosphere and photosphere into jets, such as are observed. The substances thrown up, as they fall, will produce a region of general and also selective absorption; when ,(iny portion of the descending material is liquid, the general absorption-will be great; this will then form the center of the spot. — N. Y. Sun. —The successful employment of metal bands for the transmission of power is pronounced by the Scientific Avierican an impossibility. A soft steel-band, one-twenty-fourth of an inch thick, running over a drum thirty-six inches in diameter, the latter revolving 350 times per minute, will last from eighty to one hundred days, when it will break; after splicing, it will run from about live to' eight days, when it will break again, but at this time 44 will show several more cracks, and perhaps be found to be already breaking in two or three places. The metal-band will not last one-fiftieth part as long as the leather-band under these conditions; on smaller or larger drums, the band will last a correspondingly longer or shorter period. Band saw-blades also act in the same manner. Many an apparently sound sawblade, from one-fourth to one-half inch in width, breaks every day or oftener, which it did not do when first put on; it has become brittle on account of the great, number of times it has been bent; it is in fact worn out. By using a band-saw new, the blade being from one-fourth to one-half inch width, it can be used up to one-eighth or within one-sixteenth of an inch without breaking. From a technical journal the following facts are gathered concerning a new process of brickmaking, by which a great saving in fuel, time and labor is said to z be efiected: Upon entering the works the first thing to be seen is a stone-crushing machine, into which the stone are cast and crushed to pebble size; thence they are shoveled into a pan over which two large rollers are worked, which grind them to powder. Both the pan and rollers are lined” with chilled iron. While the grinding process goes on a small white stream of a prepared liquid falls into the pan and combined with the 1 powdered stone makes a kind of mortar. This com* position is delivered to the molder, who puts it into a double mold, which is in turn set in a press. When, the bricks are forced out of the mold a lad carries them on a sheet of iron to the oven used for drying them. This oven is constructed on the same general principle, as a baker’s oven but it is considerably larger, and instead of one floor contains’several tiers made of upright and horizontal irons about five inches apart. On these the bricks are laid so tliat the oven can be filled from bottom to top. When the oven has received about 10,000 bricks the iron doors are closed up air-tight. Certain flues admit the hot air and the contents are said to be thoroughly dried in from three to four hours. —A young fellow once, offered to kiss a Quakeress. “Friend,” said she, “thee must not do it.*’ “O! by Jove! but J must,” said the youth.’ “ Well, friend, as thee hast sworn, thee may do it; but thee must not make a practice of it.’’