SCIENCE AND INVENTIONS

New Zealand Herald, Volume LI, Issue 15551, 7 March 1914, Page 4 (Supplement)

SCIENCE AND INVENTIONS

POCKET WIRELESS.

A pocket wiresless. telegraphy receiver in the form of a small telephone, Which needs . no apparatus of posts and antennae, has been, presented to 'the jrench Astronomical Society by an engineer. Tins . instrument, which slips with ease into the coat pocket, has only to be brought into contact with any metallic surface, such as an iron railing, a brass curtain rail, or the metal fittings of a motor-car to enable the listener to hear the time signals from the Eiffel Tower. Thirty miles from Paris an ordinary spade stuck in the ground forms a receiving station adequate to catch a wireless message, while a telegraph pole with its wires will serve tho same purpose to a distance of over 650 miles.

PANAMA CANAL LOCKS. For preventing leakage around the ends of the lock gates of the Panama Canal the most careful fitting and adjustment is required. Popular Mechanics describes the way of securing water-tight joints at the hinged and swinging ends of the steel leaves. Each of the four leaves of these gates is 65 feet long, 47ft 4in high, and 7ft thick, and weighs 390 tons. The leaves swing on heavy steel upright pins anchored in the floor of the lock. To make a water-tight joint with the wall a heavy steel casting with a recess in its outer surlace was set in the lock wall as it was built. A bearing plate was then set in the recess of the casting and held •4n' place by lin bolts, Ike e.id of the leaf was prepared in the same way, the steel casting being permanently attached by means of bolts. After the plates were closely adjusted hot babbit metal was poured into the spaces between the bearing plates and the castings, forcing them together to form a water-tight joint. The same method was followed in securing an exact fit in the swinging ends of the leaves. Leakage at the bottom of the leaves is prevented by means of a rubber strip five inches wide and half an inch, thick, which serves to make a water-tight joint between the wooden beam carried by the leaf and the wooden sill embedded in the floor of the lock. i ' AUTOMATIC TAXI-CAB CALLS. An automatic system of calling taxicabs which seems to be giving general satisfaction has been put into operation in Hamburg. So far Hamburg is the only city in the world in which the system is in * use, according to the United States Consul-General. Automatic machines resembling letter-boxes have been placed at every vehicle stand in the city, and are connected with a central office by an individual wire. Anyone who desires to call a carriage, and who finds none at the stand, places a mark piece in the machine, whereupon his presence is indicated immediately at the central office, which, being i already advised of the number and location of free vehicles at all other stands, immediately causes a taxi-cab to proceed to the waiting customer, -who is credited with the mark already paid into the machine when he settles for his fare. Persons who are in their own homes or places of business, and who desire a taxito be sent to them, have only to make known their wishes to the central telephone office with which the cab-calling system is provided, and the call is at ancle transmitted to the nearest, cab-stand where there are idle vehicles. , When a chauffeur draws up at a stand to await a fare he immediately inserts a slug, in the calling machine, and thereby notifies the operator at the switchboard in the central office that there is a vacant cab at that point. Each calling machine is provided with a loud call horn and a telephone, so that the chauffeur, should he .be wanted ■ in another part of the city, can be readily called to the machine and receive his orders.

EVOLUTION AND ASCENSION. The concept of evolution is very commonly associated with that of ascension, the passage from a "lower" to a "higher" type, as the saying is. A closer examination of this popular idea shows it to be lacking in scientific precision. Under--1 lying it is esthetic judgment of what appears to our artistic sense as more noble, rather than a scientifically attained conclusion. Still, the presumption is that there is 6ome measure of truth in an idea so widespread and of so many years standing. What, in accurate terms, is the characteristic trend of development by evolution? There can be little doubt that general rules cannot be laid down. The course of evolution will depend upon circumstances. But in so far as general conditions of environment change but slowly, and may therefore at a first approximation be considered constant, there is probably a correspondingly constant trend in the course of evolution. Under constant conditions the tendency is, as a rule, for evolution to proceed from simpler to complex forms. We say, as a rule, for there are unquestionably exceptions to this, cases which may be described as degeneration, but which nevertheless represent increasing adaptation to existing conditions. Now the geologist and palaeontologist are well acquainted with certain sudden breaks in the geological record, occasioned by some comparatively sudden or " catastrophic" change in the condition of the earth's crust —the submersion of a continent in the ocean, or the emergence of land from the sea, or more or less profound climatic changes. Here the constancy of conditions is broken, and forms of life which had become highly specialised, complex, particularly well adapted to the conditions that long prevailed, are now least fitted to fall in with the new order of tilings. Thus it comes that a geological " unconformity" is usually accompanied by a sudden change in fossil flora and fauna, and that in this change the "highest" types are found to have suffered most.

! A GREAT ENGINEERING WORK. The completion of Los Angeles aque- [ duct, marks the successful ending of an I arduous struggle with nature in its most rugged aspects of mountain and desert, and with powerful and subtle private interests for > the possession of a priceless supply of water. The 10 aqueducts of ancient Rome were marvels of engineering skill and durability ; but their construction stretched over a period of- five centuries, against the eight years that have elapsed since the Los Angeles aqueduct was first proposed, and the length and dimensions of the ancient Roman aqueducts bear no comparison with that of modern Los Angeles. The longest of tbe Roman aqueducts was 62 miles, while the Los Angeles aqueduct is 254 miles in length, from the intake on Owens River to the city limits of Los Angeles. The irrigation aqueducts of the Inca Indians of ancient Peril, one of which was 360 miles long, are among the wonders of the world, especially so when it is considered that they were constructed by a people .uninformed as to modern engineering science and its methods, but these probably exhausted centuries of time. The 350 miles of iron pipe line. 30in in diameter, which conveys water across the arid plains of West Australia to the gold mining districts of Kalgoorli9 and Coolgardie, is one cf the triumphs of modern constructive hydraulic engineering; but this construction, although in a hot and waterless country, was comparatively level, while the Los Angeles aqueduct bores through miles of mountains of solid rock, crosses valleys on pillars of concrete in some places," and through huge steel syphons in others, and is of far gTeater dimensions than the notable Australian structure. The great Ashokan aqueduct to supply the City of New York, now in course of construction,, is the only modern hydraulic enterprise intended mainly for domestic and industrial use that compares fairly with the Los Angeles aqueduct. The New York aqueduct orosises the Hudson over a thousand feet beneath the river bed, and it will furnish the metropolis with 500,000,000 gallons daily, at a cost, including its various reservoirs, of about £33,000,000. The Los Angeles aqueduct has not much more than half the capacity, it is true; but it is about twice as long passes through an incomparably rougher country and its cost, wbm completed, will be less than one-fifth that of the great New York enterprise.