SCIENTIFIC AND USEFUL.

Cromwell Argus, Volume XXVI, Issue 1323, 28 August 1894, Page 3

SCIENTIFIC AND USEFUL.

PARRICIDES. In Ashantee, parricides are tied hand and foot to stakes driven in the ground near a large ant hill. The ants are then irritated by sticks thrust into the entrance to their dwellings, a guard is set at a respectful distance to prevent rescue, and the prisoner is left to be eaten alive. In 48 hours nothing is left of the criminal but a neatly-cleaned skeleton. CANAIGRE. Camps of the canaigre gatherers dot the Pecos Valley and other parts of Western Texas and New Mexico. A group of tents, a portable engine, a little mill, a heap of tangled roots, a curious-looking product spread out on sheets to dry—this is the canaigre industry. Canaigre is the dry climate cousin of the sour dock which grows in the fields of the North. Above ground canaigre makes only a modest show of stalks and leaves. Below the surface it spreads and thrives until the roots are as large as a man’s arm. The tannin it contains is what makes it profitable. Thus far the margin has proved so encouraging that attempts are being made to establish canaigre farms in the expectation that cultivation will give a yield of 20 tons to the acre. Indians have known the use of canaigre for centuries. White men are just learning that it beats oak bark and every other tannin-producing growth. Most American leather is tanned with oak and hemlock barks and extracts, but the supply is said to be running out, and many practical men think that canaigre is destined to replace them. AMERICAN MUMMIES. An American explorer has exhumed seven well-preserved mummies discovered by him beneath the ruins of cliff dwellers’ houses in South-eastern Utah. This is the most important discovery of prehistoric remains ever made in that wild and inaccessible region. These mummies are in an extraordinary state of preservation, which is accounted for by the entire absence of moisture from the atmosphere and earth in that district. Among the I collection is a male of giant stature, two females and two boys. They are not bodies of the cliff dwellers, but some race who lived before them, as they were found beneath the ruins of the cliff dwellers’ habitations, and their hair is reddish instead of black, as with the cliff dwellers. Besides, the skulls are shaped like the Caucasian, instead of flattened at the back like the skulls of the cliff'dwellers. The bodies were covered with a very curious matting or blanket of wool and feathers, then packed around with cedar bark. So well preserved are the bodies that it could be told that one boy met a violent death. The moustache is still on the face of the giant, and the course of a vein may be traced in the arm of the woman. Local scientists are greatly interested, and all agree that they are the bodies of a race antedating the cliff dwellers. THE GOOD QUALITIES OF THE ALLIGATOR. It is said that in consequence of the great demand for alligator skins for boots and shoes, travelling bags, purses, See., alligators in Louisiana and Florida have become so rare that it has been feared in about ten years they will be extinct. These ten or twelve years hundreds of sportsmen have done their worst to exterminate these creatures. Formerly these animals reached a length of thirteen metres, but in the last decade no specimens were found longer than four or five metres. Since that time the number of fish have increased in those waters, but as the scarcity of the much prized material for leather makes itself felt in trade, alligator breeding-places have been established in several places. People in Florida have observed that since the disappearance of the v the water-voles have increased at an alarming rate. The good qualities of the alligator are now being remembered, how rarely it attacked human beings, and at most caught a young pig now and then. In order to check the water-vole plague the Government of Florida has granted a closetime for Alligators. HEARING ROUND A CORNER. Why can we hear, but not see, around a corner ? Some may think that this question can be answered by saying that light moves in a straight line, and sound does not. But this answer is not satisfactory. It is known that light and sound are similar in character ; each is due to the vibration of a medium, and each is transmitted in waves. Why, then, may not light spread around a corner as well as sound ? The answer is to be found in the different lengths of sound and light waves. Sound waves themselves are of different lengths, the graver sounds having waves of greater length than the more acute. Now it can be shown mathematically that the greater length of sound waves will cause the sound to be diffused around the obstruction. Hence the bass notes of a band of music are heard more distinctly far behind 4 wall than the higher notes, and as the person moves out of the “ acoustic shadow,” the more acute notes increase in distinctness. As the length of the sound waves in the air is sometimes many feet, while the length of the longest light wave is not more than -0000266 of an inch, it is no longer a mystery why we can hear, but cannot see, around a corner. THE GENERATION OF SUN HEAT. There are other ways than burning by which heat may be generated and the temperature raised beyond any limit known. A smith, by hammering a nail, with proper precautions, can make it red hot. In boring a hole with a gimlet both wood and gimlet are heated. Sometimes car axles are heated by friction till they set the car on fire. In compressing air for certain machinery it is made intensely hot, so that means have to be used to prevent it doing damage. Now it is believed that the sun is a great ball of gases and vapours, kept hot by its shrinkage in size. There is no question that the shrinkage of such a ball under the force of the mutual attraction of its particles must heat it. It can be proved mathematically—it is not a mere matter of guess work or opinion that if the sun is now shrinking at such a rate that its diameter diminishes more than about 300 feet a year, it must be growing continually hotter. If the shrinkage is less than this it may be cooling off slowly.—Professor C. A. Toung. COLOURING LANTERN SLIDES. At a recent meeting of the Royal Dublin Society, Dr J. Alfred Scott described a method for colouring lantern slides for scientific diagrams and other purposes. The author explained that the gelatine surface should be soaked and then drained. In this damp condition the aniline dyes may be applied in watery solutions with a brush; the depth of colour depending on the strength of the solution and the length of time it is allowed to act on any one spot. The colours most suitable were found to be eosin, tarlrazine yellow, vesuvin, indigo-earmine. These colours can all be mixed without forming any new chemical bodies of a different colour, and spread very evenly. Eosin is, however, liable to fade, if very pale ; it should, therefore, be painted rather more intensely if the slide is ! intended to be often in the lantern. Coloured I inks suitable for writing with a pen on plain, cleaned glass can be made by thickening solutions of aniline with 10 per cent, of dextrine, good colour for this purpose being eosin and iodine green. A good, nearly black colour may be made from writing ink, “ encrenoire,” 1 made slightly alkaline with ammonia, and 1 thickened with 10 per cent, dextrine.