HARD WICKE' S S CIENCE- G O SSIP. 



67 



Civilisation has two sides to it — bright and 

 dark. Science is just as likely to play in the service 

 of the one as in that of the other, For instance, the 

 other day Mr. Swan, the great [electrician, declared 

 that he had just seen electrical blow-pipes capable of 

 melting the stoutest iron so rapidly that to melt into 

 a fire-and-burglar-proof safe with this fatal instrument 

 would be the work of only a few minutes, and would 

 be both an easy and a noiseless operation. The only 

 drawback to the burglar using such a scientific tool 

 is that a 40-horse engine power is required before the 

 electrical blow-pipe can work ! 



Sweet and aromatic odours have always been in 

 request amongst mankind. Eastern nations especially 

 have always been noted for their intense love of per- 

 fumes. Some years ago Professor Tyndall showed 

 that sweet and aromatic odours were cooling to 

 rooms ; in other words, their presence bars out the 

 heat-rays of the sun, allowing those of light chiefly 

 to enter. An ether-spray of perfume kept up for a 

 few minutes in a summer room too hotly heated by 

 the sun has almost a magical effect in cooling its 

 atmosphere, for the reason assigned by Dr. Tyndall. 

 It has just been discovered that odours and perfumes 

 are also an antiseptic — that is to say, protective 

 against epidemic diseases in a very high degree. No 

 wonder, therefore, that ladies instinctively put their 

 perfumed pocket-handkerchiefs to their nostrils upon 

 noticing a foul smell. 



We know that fungi grow best in the dark, whether 

 that of night or of dark cellars, but it has only re- 

 cently been discovered that those exceedingly minute 

 microscopic fungi known as bacteria share the same 

 habit. They cannot bear the light, for their deeds 

 are evil. Consequently,! if you desire to purify 

 drinking-water from bacteria and other germs, admit 

 as much light to it as possible. Some very interest- 

 ing and valuable experiments bearing on this subject 

 have just been carried on in Germany by Professor 

 Buchner. Sunlight is destructive to germs ; there- 

 fore, let there be more light. Even the powerfully 

 infectious bacilli of typhoid fever, cholera, and other 

 terrible visitations cannot stand more than one hour's 

 exposure to direct sunlight. Professor Buchner 

 cultivated these foul germs in vessels, some parts of 

 which were exposed to the light and others protected 

 by darkness. Those of the germs which survived 

 were found gathered together in the dark nooks and 

 and corners, just as a flock of sheep would be col- 

 lected on a broiling hot summer's day beneath the 

 shadow of a great tree. 



The earth rotates on its axis, although some 

 people will speak of it as revolving thereon. To 

 rotate is to spin round like a wheel ; to revolve is to 

 travel round along a certain path. Thirty years and 

 more ago a very distinguished Austrian physician 

 (Reichenbach) wrote a very remarkable book, which 



was translated into English, on "Odylism." This 

 term is derived from a Greek name for a " path " or 

 "road." He was strongly of opinion that all nervous 

 patients, and even ordinarily nervous people, should 

 lie with their beds arranged due north and south, so 

 as to be coincident with the rotation of the earth. 

 The experiments he carried out at the Vienna 

 hospitals, as related by himself, seemed very wonder- 

 ful and caused much attention at the time. He 

 positively declared that highly sensitive nervous 

 patients lying east and west in their beds did not get 

 the same rest as those arranged as above. Notions 

 widely apart sometimes strangely coincide. For in- 

 stance, some engineers of eminence have recently 

 published their opinions that the most favourable 

 position for the rotating shaft of a stationary engine 

 is north and south — that is, coincident with the 

 earth's axis. 



Many Englishmen have thought any three-leaved 

 plant would serve the purpose of a "shamrock," as 

 it would illustrate St. Patrick's explanation of the 

 doctrine of the Trinity. About the middle of March 

 the question is frequently discussed as to which is the 

 " true shamrock." Of course it is one of the trefoils, 

 but even our English j pretty little wood-sorrel has 

 been honoured with the claim to the title, in this 

 country at least. In Ireland the question as to which 

 species of trefoil constitutes the true shamrock is any- 

 thing but settled ; but there seems preponderance of 

 opinion in favour of the trefoil. The small yellow- 

 flowered trefoil is a favourite for the honour of being 

 the true shamrock. Irish botanists have been in- 

 vestigating the subject, when, after the characteristic 

 fashion, it is found that certain counties vote for the 

 white clover and others for the yellow trefoil ! 



An American chemist has just published an 

 account of his discovery of a lilac-coloured dye he 

 has been able to obtain from an extract of chestnut 

 wood, treated with alkalies and kept below 50 Fahr. 

 in a stream of air for about ten hours. The solution 

 obtained therefrom is of a clear, bright lilac colour, 

 capable of staining both animal and vegetable fibres. 



For the first time a special protective coating in 

 the form of cocoa-cellulose is being used for the pro- 

 tection of naval vessels. The new American war- 

 ship, the Olympia, is being coated with this material, 

 which is of such a nature and so adapted as to at 

 once close and make good any hole which a pro- 

 jectile may cut through it. This, at least, is what its 

 promoters claim for it. The action of the cellulose 

 in closing an aperture is largely due to the way in 

 which it is fixed against the ship. Around the entire 

 circumference of the Olympia, for instance, so far 

 above and below the ordinary water-line, a tank 

 about 14 inches or more in width is being con- 

 structed, into which the cellulose is to be put and 

 imprisoned under a high pressure. When the pro- 



