NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXIV, Issue 10419, 17 April 1897, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

PRIMEVAL MAX. Br a recent discovery of flint implement! 11 r. W. J. Lewis Abbott has succeeded in pushing still further back in time the date of the first appearance of man in Britain. The tools in question were found in an ironstone " pan," or ferruginous band, in the Cromer Forest bed. Careful observations were made in order to be certain f that they really belonged to the bed in which they occurred, and had not been subsequently buried in it. In the same way care has been exercise:! in determining the question as to whether tho specimens woru really " worked flints," and not merely fragments shattered by natural causes. On this point tho opinion of several recognised authorities was obtained, and the verdict was in favour of their human origin. Mr. Abbott himself has Inni; devoted a good deal of study ti pa!i«:lithic flints, aid in order to familiarise, himself with nil the appearances that might be produced by human agency, lum himself chipped a very large number of flint weapons. With such a strong case made out lor their artificial origin, and for their really belonging to the geological horizon on which they were found, no serious objection can be made to Mr. Abbott's view of their a><o. Tho Cromer Forest bed occurs on the northern const of Norfolk, and belongs to n. scries of marine and fresh water deposits of Pliocene n;,'o. The bed* in which the Hints wore found are of ostuarine origin. Overlying tho is a series of twisted and crumpled glacial beds, and over these again occur what are known as Pain! >lithic gravel". The occurrence of pro-glacial man in Britain is a very interesting fact, but it inu. he borne in mind that human remains of a much earlier date have been stated to occur in Burma, in beds which have beon rcferrod to the Miocene period. VOLCANOES, The causes which bring about volcanic outbursts are still uncertain, though a great deal Ins boon written with conn" lenoo in support of various view*. The immediate came sootns to bo t!io presence of wator in the rocks under iho action of great heat. Release of pressure would cause this water to llish into steam, and this series of oxpiosions rapidly repeated would bring about mi eruption. But oven if this point be conceded the question as to why outbursts should take place in certain localities rather than in others still remains to b» answered, and it is to this question that divoree answers are still advocated by various authorities. Two scientists have recently considered the problem, and have arrivod at differeut conclusions. Mr. N. S. Shaler notices how, if gases are escaping from a viscous liquid, they usually maintain a regular procession of bubble iilnnir i\ path which has been opened up. He then applies this on a large scale as an explanation of the recurrence of eruptions in the uamo locality. Two factors, he hold.-, are required to product) an outburst. One is the rapid deposit, of a thick pediment, which would of course contain a considerable amount of include wator, which would bo the source of tho explosive steam. The other is that tho sediment thus deposited would have tho temperature of its lower portion rapidly raised by conduction, and thus the requisite amount of heat for the production of tho steam would be accounted for. Another author, .Mr. J. B. Woodforth, is of opinion i that tho presence of volcanoes in certain localities is duo to the fracture of rocks under tho process of folding, and ho compares tho lines of volcanic activity in the Sandwich Islands and on tho l'acitic Coast with the lines which on a email ecalo, as ho has shown by experiment, occur in rocks under strain. There is, of course, a close connection between rapid sedimentation and rock folding, as has long been rocognised. Thick, rapidly-formed deposits can be laid down only on a rapidly subsiding soabed, and this usually means that the rocks beneath are rapidly undergoing folding, and thus allowing tho subsidence to tako place. There is no doubt that in the earth's history poriols of great volcanic activity have boon gonorally preceded by periods of heavy deposition, and a fow years ago Professor Charles Lupworth drew attention to the close connection between certain great folds on the earth's surface and lines of present volcanic activity. THE NEW ROLLER SHU'. ) ] orhap3 the most peculiar outcome of recent inventive genius is the " roller boat" Ernest Bnzin, tho main features of which are now sufficiently familiar to those who are interested in the question of marine propulsion, This craft is shortly to make its trial trip from Rouen, where it) was constructed, across the Channel to London Bridge. Its successful arrival is confidently predicted by M. Gautier, a French engineer, who read a paper on the construction of the vessel at a recent meeting of the Society of Arts. Incidentally ho reiterated the claims already made for the vessel, its exceptional speed, and its power of floating even when one or two of the lenticular rollers on which it floats are damaged. This latter advantage Booms a real one. If a hole is knocked in ono of the floats it may bo turned so that the hole is uppermost. In this position it would float like a cask with the bunghole upwards, Repairs could then be readily effected. Experts are still reserving their opinion of this novel contrivance, as it lias yot to go on its trial. The principle on which it is based seems nevertheless a good one. Skin-friction is a powerful drawback to the speed of large vessels, and it great advantage is gained by reducing it to a minimum, as M. Bazin claims to have done. The seaworthiness of the Ernest Bazin is questionable, although experience may rectify any fault in that respect. It is to be hoped also that experience, or something equally potent, will rectify the ugliness of the new craft's design. The romance of the ocean will vanish if its waters are covered with roller boats. The 16-propeller 40-knob American steamship would in many ways be preferable.

OXIDISING STEEL AND IRON. A grout many parts of machinery are exposed to moisture and dampness, oven if not directly to water. It does not always protect such pieces to paint them, but they can easily be fixed so that) they will rust little, if any, if they be properly oxidised. A very good way is to make a mixture of nut galls and glacial acetic acid. After standing awhile add a grain or so of nitrate of silver or copper sulphate to a small quantity of the mixture (say one ounce or so) and the solution is ready for use. Clean the surface of the metal with pumice stone, bat do not uso emery. Dry-air slack lime may be used after pumice stone, then cover the surface with liquid, let stand until covered with a coat of oxide. A scratchbrush should then be used vigorously upon the metal and the coating, ami standing repeated twice, twenty-four hours apart. After scratch-brushing the second time, clean the surface of the inotal and rub with a little lineead oil and camphor. GROWTH OF DIATOMS. Mr. G. C. Whipple hag carried on a series of experiments on the culture of different kinds of diatoms, and finds that an abundant food supply is not the only condition favourable for their rapid increase; the temperature, the amount ot light, and other factors influencing their growth. In common with all other chlovophvllaoeous plants, diatoms will noli grow in tiio dark ; while, on the other hand, bright sunlight also kills them. The intensity of the light below the surface of the water being affected by the colour of tlio water, diatoms are found most abundantly in light-coloured water?. Different genera, however, exhibit differences in this respect; Malosira does not require so much light as Synedra. Tho weather has a marked influence on the growth of diatoms; they increase most rapidly during those seasons of the year when the water is in circulation throughout the vertical. During these periods nob only is food must abundant, but the vertical currents keep the diatoms near the surface, where there is light enough to stimulate their growth, and where there is abundance of air. Some species display strong heliotropiam, moving toward the source of light. —Technology Quarterly (Boston).