• KNOWLEDGE ♦ 



[Aug. 3, 1883. 



The mouths of tliese Hies exhibit remarkable departures 

 from the most typical insect pattern, but the comparative 

 anatomist regards their peculiar organs as modifications of 

 simpler forms. Their mouths are called " autliate, with a 

 fleshy proboscis (labium, or lip), and enclosing several 

 lancet-like organs," so says Westwood of the Diptera in 

 general, but it is only in certain genera that these lancet 

 organs are adapted to hard work. It is instructive to 

 compare the gnat's lancets and saws with tliose of the 

 breeze-flies (Taoaiii), whose instruments are here figured, 

 and their proboscis with the longer, and in every respect 

 different one of the butterfly and moth. The most for- 

 midable of our insect enemies belong to the diptera, as that 

 great group embraces mosquitoes, blowflies, breeze-flies, 

 gad-flies, etc., in this country, and also the terrible zimb, 

 and the still more dreadful tsetse, whose bite produces a 

 fatal disease in the horse, ox, sheep, or dog. 



The modifications of mouth organs in various insects 

 suggests a great lapse of time for their formation by the 

 slow process of descent with modification, and the action 

 of such a fly as the tsetse affords a striking instance of the 

 immense series of changes that may spring from the 

 peculiarities of one small creature. Take away all the 

 animals which the tsetse will not allow to live, and not 

 only is a great country rendered comparatively useless to 

 man, but its vegetation must be different in many parti- 

 culars from that cropped by herbivora, and manured by 

 their excrements. The poison of the tsetse is very 

 injurious to man, but not nearly so much as to the animals 

 he most needs. Three or four of them are said to kill an 

 ox, and yet the weight of the poison-drops they pour into 

 their \-ictim must lie quite infinitesimal. The breeze-flies 

 are not poisonous, but they sometimes attack human beings 

 after their apparatus has been dipt in decomposing filth, 

 and then serious sores result. 



NIAGARA. 



By Richard A. Proctor. 



THE brave man who earned a world-wide fame by 

 swimming Dover Straits and had earlier won an even 

 nobler name by plunging into the Atlantic Ocean during 

 storm to save (if so might be) a fellow creature's life, has 

 cast himself a prey to the remorseless wa'ers of Niagara. 

 We cannot now, in the pain and horror excited by the 

 terrible end of his mad attempt, speak as perhaps the stern 

 moralist might speak, of the wrong Webb did his name 

 and fame, the false example he set, by this last use 

 of his splendid courage. We may well believe that 

 he overrated his powers, and underrated (it would 

 be impossible to overrate) the tremendous forces against 

 which he proposed to contend. He maybe did not know, 

 what a rough estimate of the energies at work in Niagara 

 should have shown, that amid that mass of water which 

 descends from the basin below the Falls to the engulfing 

 vortex of the Whirlpool, the body of the biggest and 

 strongest living creature must be as powerless as a drop of 

 water in mid- Atlantic. We may well hope and believe that 

 no weariness of the work of life led him to barter life, or 

 ninety -nine hundredths of his life - chances, against the 

 money by which those dependent on him might live in 

 comfort. We learn that the American railway companies 

 were guiltless, at the last at any rate, of the foul 

 conduct imputed to them ; and we may well hope 

 that whatever was said of the sums Webb expected in 

 reward of his exploit, he himself was moved only by the 

 excitement of a contest with forces which other men 



deemed insuperable, but which he hoped to overcome. Let 

 undue daring be held the only fault in the brave man we 

 have lost. His example, so judged, though not free from 

 blemish, will do little harm, compared at least with what 

 it might have done had fear of life work moved him to his 

 final exploit. Remembering that in his first and noblest 

 achievement he was moved by no hope of gain or even of 

 glory we may well believe that not ignoble thoughts but 

 a lofty though unwise ambition stirred him to attempt 

 the hopeless contest with Niagara in which his brave life 

 was lost. 



Lest others, fascinated as he seems to have been by the- 

 awful majesty of Niagara, should underrate the fearful 

 power of the forces at work along the course hj which the 

 waters of Erie pass to Ontario, or deem that with better 

 luck the Whirlpool Rapids might yet Vie passed with life — I 

 venture to say a few brief words here about this marvel of 

 nature. 



Fig. 1.— THE NIAGARA FALLS, RAPIDS, ANli WlIIKLrMi IL. 



The map (Fig. 1) shows the position of the Falls 

 (tlie Horse-Shoe on the left the American on the right 

 facing directly towards the west), the Whirlpool, and the 

 Rapids, — the Upper Rapids between Iris Island and French 

 Landing, the Lower Rapids between the Suspension Bridge 



