Progress in Science.

New Zealand Graphic, Volume XLV, Issue 18, 3 May 1911, Page 44

Progress in Science.

VENUS.

Sun-Baked Sahara and Sheet of Ice.

/eV OMK very remarkable disNm cover.e- have been made in con Zfe J inxt.on with the plant Venus at the Flagstaff Observatory by Professor Ixiaell of the United States. Longcont.nued observations at this c-b--servatory have di-pelh-d the eld idea ci a cloud-covered X enus and have replaced the old conception by that of a thinly-clad body round which strong winds swept, raising enough dust to account for the planet s high reflective power. But this is the only part of the astonishing information which observers at Flagsta'tf have gathered as the results of six months' continuous watching. It is now maintained that Venus does not rotate on its axis as has been usually stated in text books. It is now held that it turns one face only to the sun, behaving, in fact, as does our own moon. The disc of the planet passes through phases in the same way as the moon, but it is always the same illuminated face which we see. This fact was first suspected by the Italian astronomer. Schiaparelli. The markings c*n the planet, which are supposed to be ■'runs’’ produced by’ winds which have persistent directions, did not a| ; ar to vary to any een-ider-abk extent raring the six months’ ob-

serration. Tie result of this state of affairs would be that one face would be continuously baked, hacked by one that would be continually chilled by everlasting night. Professor Lowell holds that in draughts of tremendous power passed from the cold side to the hot side of the planet, removing al! moisture from the sunward face, depositing it in the form of ice on the other. This action has produced a vast ice sheet which is well adapted to act as a mirror for the stars and for such light as falls upon it, thus accounting for the “'earthshine” or “earthlight” which is sometimes seen on the dark limb of the planet. To an inhabitant of the planet who could possibly endure such—to us —uncongenial surroundings as prevail on Venus, the sun would stand practically stock still in the sky. The planet has no day, no seasons, and practically no real year with which to diversify the flight of time. To further confirm the conception that the planet did not rotate on its axis a number of speetograms were taken to determine whether the light from the specific edges of the planet was receding < r advancing. The result fully- confirmed the above theory.

Pee.liwritiea of Swwnd. Professor Sihanus Thompson in the second of a course of lectures on “Sound’’ at the Royal Institution. Loudon, demonstrated by means of experimental acoustics the transmission of sound. Sound waves were transmitted, he proved, by the “cushienable” qualities of the air, or whatever other substance served as tlie conductor. To prove that waves were occasioned by the rise and fall of a surface and not by any forxatrd movement, Professor Thompson used a little model, utilised by Dr. Thomas Young at the Royal Institution more than a century ago. Sound (other than that cf an explosive sound) travelled through air, he said, at the rate of 1090 feet a second, and what happened when air was withdrawn was indicated by placing a striking gong in a glass vessel. By means of a pump, the receptacle was converted into a vacuum, when the sound gradually became fainter, and then ceased altogether. Another interesting experiment was the transmission of the tunes from a musical box in the basement of the building to the lecture theatre, a distance of 30 feet, by means ot a column of wood. Tlie stem protruded through a hole in the floor and when a violin cr a wooden tray was placed on it the music could be plainly heard. This was the explanation of a remarkable concert given at the old Royal Polytechnic in 1823. The audience then only saw four harps standing by themselves on the stage. Further demonstrations showed how sounds travelled quicker through water than through air. and the discovery made only a month ago. that foam deadened sound, was referred to by Professor Thompson, and formed the subject cf an expeiiment with a wine glass, which rang cut clearly when elean, but gave out only a leaden noise when struck after having bee.i dipped in soap suds.

Lactic Arid and Its Use*. ’W? The physiological action of laetle aett is not yet thoroughly understood. Reeent experiments show that lactic acid, added to the food of various carnivorous and herbivorous animals, does not exert any toxic action, unless the dose is very large, exceeding five per cent of the weight of the food. Even in this case the effect is merely that of excessive acidity. Owing to its antiseptic power, which is equal to three-fiftha that of carbolic acid, lactic acid aeta as a stomachic disinfectant and a regulator of the bowels. It might certainly ba substituted with advantage for aeetic, tartaric, and citric aeids in food, and in the manufacture of confectionery and other alimentary products. ♦ ♦ ♦ Huu Gem Carriers, By far the most interesting feature cf the medical officer's report for the year 1909-10, which forms a supplement to the 39th annual report of the Local Government Board, is the review of enteric fever “earners,” with the histories of some of the most noted case-, and details of steps taken to detect them and to treat them with the hope of a “rare.” A “earner” is a person who. either after complete recovery from the disease, or apart from any known attack of illness, harbours and discharges the germs —a "human storehouse of infection,” in fact. Investigations made by Dr. Theodore Thomson and Dr. J. C. G*. Ledingham, of the Lister Institute, show that no efficient treatment of "carriers” has yet been found. Dr. Ledingham estimates that the proportion of germ carriers in an ordinary, population is roughly about three or four to the thousand. Among the many eases described by Dr. Ledingham are several in which servants have caused outbreaks on farms whern they had been employed, and deaths have occurred before the “carrier” has been detected. "In one ease a farmers wife was the ‘germ storehouse.’ Her daughter was attacked, a sister-in-law of the farmer and her two daughters (who were living in the neighbourhood as summer visitors and getting milk from the farm) werd taken ill, a child aged thirteen months, another aged nine months, the husband, a brother who assisted with the farm work, and a man servant—al] between 1892 and 1897. “In a German case a baker's wife was the ‘carrier? Every fresh apprentice, for some years, became ill. and the baker’s wife attributed these eases to ‘too good diet? ” ,