Science Siftings

New Zealand Tablet, 9 January 1913, Page 51

Science Siftings

By ‘ Volt.’

Make Ivory from Milk. One of the latest discoveries of the synthetic chemists is how to make ivory out of nothing more wonderful than cow’s milk—and a very good ivory at that, according to all accounts. The original idea was to use the new ‘ ivory ’ for piano and organ keys, because it preserves its original color indefinitely, whereas the genuine article turns yellow after a time. But it has been found that the new product is not only an efficient substitute for ivory_, but can easily be prepared so as to take the place of amber, horn, coral, celluloid, and such-like products, and, it is claimed! can hardly be distinguished from-them. It is in its position as a substitute for ivory that the new material has caused most surprise, however, because it has the appearance of being another instance of improving upon Nature. The new ivory takes a very high and lasting polish, and probably will not lack a commercial field for itself as natural ivory continues to grow scarcer and dearer year by year. A Fallen Landmark. When the famous rocking stone of Tandil, in the southern part of the province of Buenos Ayres, fell recently from its'' narrow platform on the , edge ’of a . cliff, Argentina lost one of its most interesting natural curiosities. This great granite block was more than 16 feet in diameter and 13 feet high, and weighed about 7000 tons. It was balanced so nicely that the strong winds from the pampas made it rock perceptibly, and great numbers of tourists amused themselves by clacking nuts and empty bottles under it*. Yet many years ago, the tyrant Rosas, with a team of 60 oxen, tried unsuccessfully to pull it down. It is thought that the hard pulverised glass from the thousands of broken bottles left on the cliff by visitors gradually wore away the stone and the foundation, until a slight shifting of weight caused the boulder to fall. b Submarine Signalling. The submaiine signal-bell is one of the most useful aids to navigation that have been perfected in recent years. By means of it, signals are sent at regular intervals from lighthouses'- and light-ships in foggy and stormy weather. These signals are heard by telephone in the pilot-houses of vessels that are equipped for receiving them, and make it possible for captains to find their positions on the chart in the thickest fog An American, Mr. Arthur J. Mundy, in collaboration with Prof. Elisha Gray, invented the apparatus for submarine signalling. There are now 138 stations for sending submarine signals, and more than 900 ships* have receiving apparatus. Of the sending stations, 53 are at American lighthouses or on American lightships; Canada has 14, Great Britain 27, Germany 16 France 7, Holland 6, and Belgium 5, Russia and Sweden have two each, and Argentina, China, Denmark, Portugal, Spain, and Uruguay one each. The Size of Animals. Professor Karl Sayo draws attention to the fact that animals were vastly larger in prehistoric times. He points out that even now aquatic animals reach a very considerable size, as in the case of the whale, and he suggests that this may be in part due to the buoyancy of the water, which as it were counteracts gravity, and renders large animals more mobile than they could be on terra firma. It might, therefore, be supposed that in past geological ages the weight of bo ' u j Ol tle ea . rt k was less than to-day, and thus enabled large animals to make a successful' fight for existence under circumstances in which they could not now survive. As a possible cause of increased weight in our present epoch it is pointed out that the earth formerly revolved faster, and that hence centrifugal action was greater. But that seems a very far-fetched and highly improbable explanation.