July 1, 1897.] 



KNOWLEDGE 



161 



normally an insulator, but conductors when electric waves 

 fall on the particles. A passing current, therefore, was 

 arranged to ring a bell, or signal in other ways ; but to 

 render the fihngs again non-conductive, a local current is 

 made to work a hammer-head which shakes the filings 

 back into an insulating condition — a receiver, indeed, 

 which, as Mr. Preece says, is "about the most delicate 

 electric instrument we possess." By its aid signals have 

 been transmitted across the Bristol Channel between 

 Penarth and Brean Down, a distance of nearly nine miles. 

 If a receiver is to respond to a certain transmitter it must 

 be timed to accord with it, or, if not so timed, no effect 

 will result. It is curious that hills and other obstructions 

 fail to retard the effects, nor has the weather any inriaence, 

 while the receiver may be placed in a perfectly closed 

 metallic box without entailing any baneful effects. Mr. 

 Preece considers that the employment of this device in 

 the public service would greatly enhance those ends and 

 aims where secrecy is the dominant element. Enough 

 has been done to show its value in that direction, and for 

 shipping and lighthouse purposes it is regarded as a 

 priceless acquisition. 



And who gathers in the firstfruits of new scientific 

 discoveries ? Is it the people — is it humanity as a whole ? 

 No ; the Government is the reservoir into which all the 

 new things worth having flow, and we get just what 

 escapes through the leaks. What does the Government do 

 to help on the band of workers who are patiently groping 

 their way through the dark unknown '? Four thousand 

 pounds a year is all that we get — less than the crumbs 

 which fall from the richly furnished tables of our naval 

 and military protectors. Chemistry has supplied them with 

 explosives, electricians with easy channels of communica- 

 tion — harmless and otherwise — engineers with steam 

 hammers, etc., which have rendered possible the making; 

 of heavy ordnance ; and these, and a thousand other 

 products of scientific thought and action, drift in the main 

 to protect us from our possible enemies. Sir Lewis Morris 

 says : " The whole of Europe is one immense camp, 

 maintaining in idleness, out of the labour of the people, 

 millions on millions of young men, armed with weapons of 

 incredible cost, marching and counter-marching futilely 

 over every European country, not adding one penny to the 

 national wealth — a canker at the core of civilization, a 

 constant source of corruption and vice, sinking Europe in 

 bankruptcy, sapping by their vices the precious vigour of 

 the race, filling men — and women, too — with ideas of false 

 glory deeper than the lowest depths of shame, perpetuating 

 narrow jealousies and suspicions fatal to any idea of the 

 brotherhood of man." It would be a glad day for science 

 in England if in this year of Jubilee our Government could 

 be induced to begin to look with more appreciation on 

 those who contributed so much to make the sixty years of 

 Queen Victoria's reign unique in the history of the world. 



There is, indeed, no vein of science too abstract for 

 future industrial apphcation, not yet thoroughly mined 

 out and exhausted. The everyday progress of the arts 

 abounds in new applications of objects the most familiar. 

 Science may see an horizon bounding her view, but as she 

 proceeds onward the horizon constantly recedes, and shows 

 the limit to be altogether illusory. As we have seen, the 

 growth of scientific discovery is slow. In its study we are 

 never sure that the morrow may not gladden the world 

 with an application of a principle to-day abstract, and 

 apparently remote from practice. Science is too lofty for 

 measurement by the yard of utility — too inestimable for 

 expression by a money standard. There never was a time 

 when it was so necessary as now that skill and science should 

 be united for the promotion of the industrial arts. Intellect 



is on the stretch to get forward, and that nation which 

 holds not by it will soon be left behind. And how, except 

 through earnest scientific study, can we attain the 

 knowledge that shall enable us to discover the pathway 

 leading towards perfection ? Eemember the words of 

 Lactautius, when the Council of Sages at Salamanca 

 negatived the idea of a western continent : "Is there any 

 one so foolish," says he, " as to believe that there are 

 antipodes with their feet opposite to ours ; people who 

 walk with their heels upwards and their heads hanging 

 down •? That there is a part of the world in which all 

 things are topsy-turvy ; where the trees grow with their 

 branches downwards, and where it rains, hails, and snowa 

 upwards ? '' In looking hopefully into the future let us 

 remember this, and be not dismayed because of the sneering 

 cry, Cui bono .' 



ON THE VEGETATION AND SOME OF THE 

 VEGETABLE PRODUCTIONS OF AUSTRAL- 

 ASIA.-III. 



By W. BoTTiNG Hemsley, F.R.S., F.L.S. 



IN order to avoid crowding all my figures illustrating 

 flowers and fruits, or seed-vessels, of the gum trees, 

 into one article, I described the peculiarities of the 

 structure of the flowers in my last. It would have 

 been more in accord with development to have com- 

 menced with the tree itself, and followed with its leaves, 

 flowers, and seed-vessels ; but it is not a point of impor- 

 tance here. 



Dampier likened the gum trees he saw to apple trees in 

 size, but the different species exhibit great diversity in 

 habit, some of them, indeed, not being trees. I have said 

 that they range from north to south, from the hottest of 

 tropical regions to the temperate south ; a few of them 

 also reach the tree limits in the mountains of Tasmania 

 and South Australia, where snow and somewhat severe 

 frosts prevail during several months of the year. Two or 

 three species ascend even to altitudes of four thousand to 

 five thousand five hundred feet in the Australian Alps, 

 where, however, they only attain the dimensions of small 

 shrubs, flowering and fruiting when two or three feet high. 

 On the other hand, several species attain enormous dimen- 

 sions in favourable situations, such as deep glens, and 

 exceptional trees are the tallest in the world. Particulars 

 on this point will follow. 



I will now try to give an idea what a characteristic 

 large gum tree is like. In foliage it more nearly resembles 

 a narrow-leaved wiUow than any of our other trees, but 

 the leaves are much thicker, usually more or less oblique, 

 or sickle shaped, and the surfaces are vertical instead of 

 horizontal, as in most other trees. This disposition of 

 the leaves exposes the smallest surface to the direct 

 rays of the sun, an arrangement believed to be of great 

 advantage in the domestic economy of the tree, taking 

 into account the climatic conditions. In habit — that is 

 to say, in outline, manner of growth, branching, and general 

 appearance — there is great diversity in gum trees, some 

 bearing a resemblance, as Dampier states, to large apple 

 trees ; but the characteristic of the very tall-growing ones 

 is a massive trunk, branchless to a great height, and a 

 comparatively small crown, with the ultimate branchlets 

 slender and drooping. In seedlings and young trees, and 

 in shoots arising at the base of the trunk, the leaves are 

 commonly in pairs, one opposite the other, of a larger 

 size and different shape, and with the surface spread out 

 horizontally. The presence of numerous glands in the 



