SCIENCE NOTES.

Otago Witness, Issue 2241, 11 February 1897, Page 48

SCIENCE NOTES.

■ . The phenomena of rain are imitated by Professor Errera, of Brussels University, in a beaker. The glass, Bin tall by Sin in diameter, is half filled with 92 per cent, alcohol, covered with asaucer.and thoroughly heated over a water bath without boiling the liquid. It is then carefully removed to a wooden table. Soon the alcohol vapour is condensed into visible clouds by the cooling saucer, innumerable miniature droplets of rain fall, and the clouds become gradually lowered away from the saucer. The miniature etorm may laet half an hour. The action is intensified if the warm saucer is replaced by a cold one. Whirlwinds and squallß are produced when the alcohol is very warm, and if the liquid ia warmer on one side the clouds may be seen to rotate around a horizontal axis. • . • The Museum afc Oxford, with its priceless contents, recently ran a narrow escape of being destroyed by fire. During a severe thunderstorm the building was struck by lightning, and the roof was fired : but luckily help was at hand, and by cutting away some of "the burning woodwork the building was saved. The important point to be noted in this incipient conflagration is that the museum was furnished with no fewer than four lightning conductors ; but the lightning struck a gable which was unprotected, and the electricity seemg to have travelled along a lead gutter and down a standpipe to the earth. The occurrence' shows that a building only partially protected by metal points is in almost as sorry a condition as one that has none at all. . On the subject of the prevention of ! colliery explosions the Hospital writes : [" In every way coal dust is a cause of 4iaaatar. Ifc jajjomotas explosion, it widens

I its effects, and it poisons those within its area. Yet the prevention of ifc i 9 an extremely difficulc matter. By every stroke of the miner's pick as he * holes ' the coal, by every fall of coal, by every action, in fact, by which coal is touched with tools dust is produced ; so that ultimately every ledge and cranny in the mine becomes a lodgment for an accumulation which only requires to be dry and to be shaken to create an exploßiye mixture. The obvious suggestion ia to water the mine, and, in fact, up to the present time sweeping and watering are the only known means of lessening the danger from the presence of coal dust in mines. It is important, however, to bear in mind that the production of such a dampness of atmosphere as to prevent the drying o£ the dust is itself likely to be productive of diseases which, if not so sensational in their denouement, at the least tend to be quite as fatal in the end. It is perfectly plain that no mere watering of visible dust is likely to be of much service. The only way of preventing the dust from becoming diy is so to saturate the air with moisture as to prevent it from absorbing moisture, all of which means that. the miner must work in an atmospheie approaching the saturation point. This bringß us face to face with the real question, because there is plenty of experience as to the evil effects of working in a saturated atmosphere." • . • In a building io New York city, which is let out in sections, compressed air is added to the list of conveniences at the service of tenants. An air compressor is placed in the engine room of the building, and air power will be supplied to all the tenants of the building who desire it. The compreasor is run by steam, and compre&ses the air into an air receiver. The building is piped throughout, pipes being run up through the Ehafb and branches taken off at the floors. The plant has been pub down by a company having large interests in compressed air apparatus, and is intended to demonstrate the number of uses to which compressed air can be put in ordinary business and domestic life. ' • . • One of the most curious results of the investigations made by doctors in the Russian gaols is the statement that each groap of criminals has its own peculiar colour of the eye. A legal journal at Odessa states that ifc has been found that thieves and murderers usually possess " chestnut- brown " eyes. Robbers — that is to say, thieves in a large arid violent lino of business — have slatecoloured eyes, and the same ie stated of criminals convicted of swindling. The vaga- ! bond classes, among whom are probably reckoned the passponlesa class, have eyes of szure-blue tint. The colour most observed amocg mJnov ctemnals and those convicted of slight offences is " chestnut-brown green." • . • Carbolic acid ia now so generally employed for disinfecting purposes that familiarity is apt to breed contempt for its highly corrosive and poisonous qualities ; hence the value of knowing of a «ood and ensily obtained antidote to its dangerous effects. Professor Carleton states that vinogav applied to a cutaneous or mucous j surface which has been burned by the acid will immediately give relief, the characteristic bleaching of the skin quickly disappearing, and subnequent scarring being to a large extent prevented. It is also useful when the poison has been taken internally ; ! and, unfortunately, largo numbers of lives ! are lost annually through carbolic acid j poisoning — chiefly oases of suicide. For Internal administration the vinegar should be diluted with an equal quantity of water, and taken by the patient as soon as possible. • • A new process for the manufacture of steel, invented by B. Stockman, of Manchester, England, is claimed to be a success. The process involves a combination of both the Bessemer and the open-hearth methods of manufacture, and it is a basic dephosphorising system. The molten phosphoric iron is brought into contact, in a converter or similar vessel, with dephosphorising agents — nitrate of soda, common salt, and titanic iron sand being the cnief ingredients— and j after a contact of only three minutes the j metalloids are practically eliminated. The metal is then poured into an open-hearth melting furnace, where it is treated for about two hours, during which time the dephosphorisation and desulphurisatioHL are completed, and the carbon is added in the usual way, as spiegeleisen or ferro-manganese. The steel produced by this system has been tested by Kirkaldy, of London, and Nash, of ! Sheffield, and the results are said to be aatis- : factory. It appears to be adapted to the production of steel of any degree of hardness, and as it only occupies about two and a- quarter to two and a-half hours it is comparatively inexpensive. • . • That the rays of the moon are at times cathode, and capable of penetrating opaque i substances, is the latest discovery. Pro- ! fessor Rontgen's apparatus is thus supplied | by Nature, and is within the reach of everybody. The maker of this scientific "dis- i qggerv " is a German electrician, G. Dohr- | man. of Bremen. He is now workiDg with a number of other electricians, and the results they have obtained are receiving serious attention in Germany Mr Dobrman claims he has proved that a photographic negative protected from light receives an impression from the rays of the moon while it is absolutely unaffected by sunlight. The only conclusion to be drawn from Jhis is, he says, that the moon's rays are capable of penetrat- ' ing the covering of the plate. i ' • . •It is well known that a, Darson weighs

no more after deliberately oattag a hearty j meal that he did before. A little reflection I will readily explain tbiß apparent mystery. | Daring the process of eating "certain musolei! I are brought into aotive play, and the exercise of any musolo necessitates a temporary waste of its tissues, while a cortaln amount of carbon ia eliminated and passed off during the course of tbe meal. This loss, however, i 6 trifling compared with that of respiration and perspiration, both of which are increased. The length of time one may take to consume a pound of food makei no little diff .srance to these losses, for if eaten leisurely there ia but slight increaso of respiration or perspiration, whereas if ib is hurriecL. through both these processes are abnormally accelerated. Hence by tbe time the pound is eaten the consumer has in reality lost appreciably in moisture or carbonic acid.