PROFESSOR DAVID.

Auckland Star, Volume XXXVII, Issue 254, 31 October 1906, Page 8

PROFESSOR DAVID.

AUSTEALIAN SCIENTISTS' TOUR. VISIT TO MEXICO. WONDERFUL, PROGRESS UNDER PRESIDENT DIAZ. Professor David, of the University of Sydney, who is a passenger by the' s.s. •Sonoma, is returning to Sydney after a five months trip around the world. Having been invited by the Congress to contribute a paper on "'Changes of Climate," at the International Geological Conference at the city of Mexico," and to take part in the discussion, he was given the necessary leave of absence .by the Senate of the University, and left Sydney on May 22nd. Colombo was reached on. June 10th, and crossing the Gulf of Manaar to Tuticorin. he travelled by train to Madras, and thence along the coast and over the Kostua and Godavery rivers to Calcutta.' Arrangements were there made for him by the Geological Survey and Chief Inspector of Coalmines near Chanda in "the central provinces. Leaving Calcutta he proceeded to Chanda. and examined the remarkable old glacial strata which near Chanda underlie the ninety feet coal seam, the thickest and largest seam worked in India. These glacial beds cover a vast area, and- actually range from about 18 deg. North latitude, a distance of over 100 geographical miles. Their height above sea-level is now only about 600- feet, and there is no evidence to show that the land, at the time of the glaciation, stood any higher than it docs now. It is one of the most striking examples of change of climate that could well bn imagined. The. monsoon rains burst with great violience while he was finishing some field work in this district, and some difficulty was.experienced in crossing some of tue flooded upper waters • of the Godavery River, in order to return to Chanda. From Chanda he went to Bombay, and thence via Aden- and the Suez canal to Marseilles, and on thence to Paris and London. He attended the annual meeting of the British Association for the Advancement of Science at York, commencing on August Ist. and read two papers, one on the coal-fields of New South Wales, and the other on the occurrence of diamond in matrix near Invercll, in New South Wales. From York he went via Liverpool to New York, where some time was spent at the American Museum of Natural History in writing up his observations in India on Changes of Climate. Boston and Harvard were also visited, and after five and a-half day 3 of continuous travelling day and night by express trains, the city of Mexico was readied. THE CITY OF MEXICO. At the time, of the Spanish conquest of Mexico by Cortes —Mexico, the old city of the Aztec?, built largely on piles and causeways in a large lake, with its floating gardens, its great pyramids or teocalli, its palaces, and fleets of canoes and fishing boats—has been described by the historian Prcscott as the "Venice of the West."' All this has been quite changed since the coming of the Spaniards in 1519. The old lake has been largely drained by deep and wide artificial canals; the lake floor thus reclaimed has been levelled up, and built over, and all the old Aztec buildings, temples and pyramids of the ancient city have been swept away. Mexico, with its busy shops, its electric lighting system, and its street cars and railways, has now the appearance of any.modem city. Tt3 population is about 400.000. while that of the Republic of Mexico is about 14 millions. The situation is most romantic. It lies in a great plain or plateau over 700 feet above the sea, green with crops of maize, and inaquey (the Mexican aloe. Agave Americana), while at a distance of 30 to 50 miles the plain is bounded by the gigantic range of the Mexican Andes with snowcapped' peaks of Popocatepetl and Ixtaccihuatl piercing the clouds and towering aloft into the blue sky. Under the strong beneficent rule of President Porphyrio Diaz Mexico has of late made wonderful progress, and now is rapidly developing into a powerful nation. This forward movement is being hastened oy the inflow of American, German, and English capital, and there are quite a number of German merchant's and American mining engineers and American ranchers and orchardists settled in Mexico. The Mexican population is, to the extent of over SO per cent, Indian. the remainder being partly Spanish or mixed races, sprung from intermarriage of Spanish and Indians, or immigrants from the United States or Europe while the people are intensely patriotic, and cherish their liberties most dearly, they have adopted the enlightened policy of freely admitting desirable immigrants from other countries, and allow other countries to come in without restraint, anrl assist in the development of thennatural resources. THE RICHNESS OF MEXICO. Mexico is a country exceedingly rich In mineral wealth, particularly in silver and copper as well as gold, and with its wondsrful range of climate, from tropical to Arctic, its good rainfall and fertile soil, it will grow almost anything. The general impression among the -300 fove/ign Coriiressists at the science meeting was that Mexico ha 3 a great future before her. A week was spent by the Congressists in the city of Mexico, in the reading of papers and in discussions. As regards changes of climate the evidence from Australia and India excited much interest, as did the large collection of ancient glacial specimens from Australia. Tasmania, and India. Although no definite conclusion was come to in the discussion, the opinion held by many Congressists as to the causes of past changes of ■climate had developed ice masses in the heart of Australia, India, and South.Africa just before the great coalfields of these countries were about to farm, was that in the first case they were due to changes in the amount of heat received by the' earth, from the sub. .. - CAUSES OF CLIMATIC VARIATIONS. The experiments by the late Professor S. R. Langley, of Washington, showed that the sun's iheat now could vary from time to time by as much as 10. per cent. Probably small changes of weather such, as bring about alternations of good. and bad seasons, at the present time are dependent en such variations. While variations in the amount of heat received by tlis earth from the s\m might be the primary factor in prctjucing small changes in, present climate, and large change's in the past, it was thought that these conditions, might be further modified by changes in the composition and thickness of the earth's ■. atmosphere, as well as by ffchja distribution: of■■• land and water, •which in-turn partly, controls prevalent winds and ocean currents, and rainfall and snowfall. Jjiere was an interesting discussion on the 'genesis of ore de-

posits, and much'useful information-was gained, after the Congress was over, by extended excursions to the principal Mexican mines. SOME INTERESTING EXCURSIONS. Some of the principal- volcanoes of Mexico such as the active cone of Colima, the snow-capped craters of Orizaba and Popo.eatepetl were explored by some of the Congressists. as well as the local sulphur mines, and crater lakes. Excursions were also made to the ancient ruined palaces and temples of Mitla, and the great pyramids of the Sun and Moon at Teotilmacan. The latter was a particularly interesting trip, and rather exciting for the scientists. They were mounted on the spirited war-horses of the 14th Cavalry Regiment, and many of the riders, being more used to a professorial chair than to a Mexican cavalry saddle, urged on their wild career on the big bolting horses to their own undoing. Fifteen of the Congressists -were pitched headlong in the dust, and a large proportion of the remainder had great difficulty in. keeping their seats. Fortunately all escaped with nothing worse than a few cuts and bruises arid shock to the system. The pyramids of Teotihipiean, ■which are comparable in size to many of the pyramids of Egypt, are inferior to them in architecture, being built simply of earth faced -with rough masonry. The temples at their summits nd basis have now been destroyed. The remains are very old, these pryamids, built by the Toltecans, predecessors of the Aztecs, being already in ruins at the time of the. arrival of Cortes in 1519. The ground in the vicinity of these pyramids abounded in remains of Toltecan pottery and arrow heads, swordteeth, knives and razor-blades made of the black bottle-gkss-like volcan'c glass Obsidian. There were also vast quantities of rude pottery, and small images of the household, gods of the Toltecans. These relics could be collected literally in bushels. The Mexican Government was extremely liberal in its entertainment of the Congress, as were all the provincial towns visited. The Government coni veyed the Congreesists by train all over the country free of charge. The Congress was certainly highly interring and enjoyable as well as successful, from a scientific point of view. NOTES IN THE UNITED STATES. On his return from Mexico, Professor I David visited the Grand Canon of Colorado, and made the descent of nearly 6000 feet into the Colorado river. From the Grand Canon he proceeded via the Mojavc Desert and tha important new Bakersfield oilfields, and I the great orchards of the San Joaqu : n Valley to San Francisco. From San Francisco he visited the neighbouring Stanford University, where Professor Branner took bim along the line of the great earthquake crack. It is a wonderj ful sight. Mostly it looks like a huge I furrow in the ground; in places it is a gaping chasm. It has been traced already foi- ISo niilfs, and probably extends for at least 300 miles. This great I crack gave rise chiefly to a horizontal ! movement, whereby a slice of the ! American Continent, next to the Pacific some 50 miles wide and 400 miles long, was moved permanently forward in a north-westerly direction to the extent of 10 feet. Although great energy is being shown in the. work of. je-con-struction it will be many years before either ; Standford University-is fully repaired, or San Francisco re-built. Professor David wa,s specially, impressed, in his visit to Mexico and the United States, -with the great use that is made !of water power for generating electricity, and with the long distances, often 100 to 200 miles or more, to which the power is transmitted. For.example some of the ebicf Mexican mines have all their machinery driven by electricity transmitted from waterfalls over 80 miles distant from the mines, -while in San Francisoo the source of electric power for the city is in the Sierra Nevada Pianges, 200 miles distant, and at Los Angelos, also in California, the power station is 250 miles distant from the city. He was also impressed With the extensive use that is made of oil !as a source of energy in the United States, oil being used exclusively as a i fuel on many of the American railways, and on numbers of steamers.