HARDWICKK S SCIENCE-GOSSIP. 



"7 



and clouds are practically the same. One descends 

 to the earth under special local conditions, the other 

 remains suspended in the atmosphere. But there 

 could be neither clouds nor fogs without dust, around 

 every floating particle of which the moisture con- 

 denses. Hence in cities like London, where there is 

 such a vast quantity of coal-dust in the shape of 

 smoke, daily poured into the atmosphere, it cannot 

 he wondered at that fogs should accumulate and 

 abound, especially during those periods of still weather, 

 termed " anti-cyclonic, : ' when the bulk of the 

 atmosphere is stationary. Professor Oliver shows 

 that the waste products thrown into the air produce 

 different effects upon the leaves and flowers of plants. 

 Phenol turns them black. Sulphurous acid, so 

 prevalent in fogs, kills white flowers at once. In 

 short, the different ingredients in city fogs appear to 

 have each its own destructive method of attack. 

 Thick-leaved plants, such as holly and aucuba, even 

 even when covered with deposit of fog, remain 

 healthy on account of the thickness of the leaves, 

 which contain two or three rows of cells, instead of 

 one layer only, as in other plants. 



Most of our readers are aware that if they 

 purchase a number of pill-boxes for any purpose 

 they are "nested" one inside the other. How little 

 do w'e know of life, or of the messmateship of living 

 organism ? For instance, in the last number of the 

 "Journal of the Royal Microscopical Society" there 

 is an elaborate paper by Mr. C. H. Gill, giving the 

 natural history of a parasite on diatoms. Diatoms 

 are prettily-shaped, prettily-marked, single-celled 

 plants, with a silicious or glassy skin. In this 

 instance the host plant is only the three-hundredth- 

 part of an inch in length, but, minute though it be, 

 it has a parasite all to itself, of course infinitely 

 smaller, and Mr. Gill has carefully worked out its 

 life-history in his paper, which is illustrated by nine 

 photographs, showing the different stages of the 

 parasite's development. 



At the last meeting of the Royal Society Professor 

 Dewar stated he had succeeding in freezing the 

 atmosphere into a clear, transparent solid, although 

 at present it has not been sufficiently proved whether 

 the mass was a jelly of solid nitrogen containing 

 liquid oxygen, or a true ice of liquid air into which 

 both these well-known gases have been equally 

 solidified. 



Professor George Henslow recently delivered 

 a lecture at the Royal Horticultural Society on the 

 ■subject, not only of cultivating flowers, but of ger- 

 minating seeds under coloured glass. This is a most 

 important matter just now, for in a few years many 

 of the Channel Islands will be half covered with 

 glass, to say nothing of the warmer parts of southern 

 arid south-eastern parts of England. It is beneath 

 these extensive glass-houses and frames the enormous 



quantities of early vegetable delicacies that we enjoy 

 — asparagus, sea-kale, early peas, new potatoes, 

 strawberries, to say nothing of tomatoes, flowers, etc. 

 — are grown. What is the best tint of glass under 

 which forced plants can be grown? Thus, lilies 

 of the valley seem to gain by a fortnight when grown 

 in a violet-glazed house. Green glass seems to be 

 the worst of all. For the germination of seeds tolal 

 darkness is the best, and for all green-foliaged plants 

 free light and air are to be preferred. 



Professor Crookshank recently gave a lecture 

 on "Bacteria" (the microscopical funguses we have 

 hitherto regarded as only baleful, but which are 

 actually amongst mankind's best friends). One great 

 group produces fermentation, so that without them 

 we should have neither wine nor beer. Another 

 division is the cause of organic decomposition, 

 amongst which must be reckoned the nitrifying 

 bacteria of the soils. If it were not for the latter 

 group every animal that died would be as inde- 

 structible as an Egyptian mummy, inasmuch as the 

 art of "mummifying " consisted in keeping away the 

 decomposing bacteria. If it were not for the latter 

 the surface of the earth would be piled with dead 

 bodies, stacked in heaps or choking the rivers ; not 

 only that, but in time all the elements capable of 

 building up living bodies would be used up — locked 

 up in these corpses — and life would cease for lack of 

 material to support it. The greatest enemies to this 

 class of bacteria are the undertakers ! 



Jupiter is thirteen hundred times larger than the 

 earth, so we take a great deal of interest in it, and its 

 careful study of recent years has thrown a great deal 

 of light upon the history and manufacture of worlds. 

 One of the keenest astronomers, who was taking 

 special charge of this huge globe, is Prof. Pickering, 

 the distinguished American scientist. In order to 

 study the planet more definitely he has been residing 

 on the top of Arequipa, in Peru, on account of its 

 clear and cloudless atmosphere. He writes from 

 there to state that the surface of Jupiter seems to 

 consist of a uniform white mass of cloud, over which 

 is stretched a gauzy and thin veil of brown material. 

 The well-known belts of Jupiter, he says, are simply 

 dense masses of this thin brown material, and the white 

 spots merely holes seen through it. The most re- 

 markable thing about Prof. Pickering's observations 

 concerns the moons or satellites of the planet. He 

 has arrived at the conclusion that Jupiter's four 

 moons are not solid, like ours, but merely condensed 

 masses of meteorites, like those which compose the 

 belts of Saturn. 



There is a glamour about the beginnings of life, 

 geological as well as biological, which attracts 

 scientists in the same manner as the speculations of 

 theologians concerning the life to come. For ex- 

 ample, a distinguished German physiologist, Prof. 



