Ttility 



SCIENTIFIC SIDE-LIGHTS 



722 



a theme for disputation or declamation has 

 no such motive. He is therefore content 

 with premises grounded on assumption, or 

 on the most scanty and hasty induction. 

 Thus, we conceive, the schoolmen acted. On 

 their foolish premises they often argued 

 with great ability; and as their object was 

 " assensum subjugare, non res " to be vic- 

 torious in controversy, not to be victorious 

 over Nature they were consistent. For 

 just as much logical skill could be shown 

 in reasoning on false as on true premises. 

 But the followers of the new philosophy, 

 proposing to themselves the discovery of 

 useful truth as their object, must have 

 altogether failed of attaining that object if 

 they had been content to build theories 

 on superficial induction. MACAULAY Essays 

 (Lord Bacon), p. 283. (A., 1876.) 



3577. UTILITY, DISCOVERY OF 

 UNEXPECTED Nature Sifts the Food of In- 

 sectivorous Plants Marginal Spikes of Ve- 

 nus's Fly-trap Escape of Useless Insects 

 Provided for. We are now prepared to un- 

 derstand the use of the marginal spikes 

 which form so conspicuous a feature in the 

 appearance of the plant [Dion&a muscipula, 

 or Venus's fly-trap], and which at first 

 seemed to me in my ignorance useless ap- 

 pendages. From the inward curvature of 

 the lobes as they approach each other the 

 tips of the marginal spikes first intercross, 

 and ultimately their bases. Until the edges 

 of the lobes come into contact, elongated 

 spaces between the spikes, varying from the 

 j^to the ^ of an inch (1.693 to 2.54 mm.) 

 in breadth, according to the size of the leaf, 

 are left open. Thus an insect, if its body 

 is not thicker than these measurements, can 

 easily escape between the crossed spikes, 

 when disturbed by the closing lobes and 

 increasing darkness; and one of my sons 

 actually saw a small insect thus escaping. 

 A moderately large insect, on the other hand, 

 if it tries to escape between the bars, will 

 surely be pushed back again into its horrid 

 prison with closing walls, for the spikes 

 continue to cross more and more until the 

 edges of the lobes come into contact. . . . 

 Now it would manifestly be a great disad- 

 vantage to the plant to waste many days 

 in remaining clasped over a minute insect, 

 and several additional days or weeks in 

 afterwards recovering its sensibility, inas- 

 much as a minute insect would afford but 

 little nutriment. It would be far better for 

 the plant to wait for a time until a moder- 

 ately large insect was captured, and to al- 

 low all the little ones to escape; and this 

 advantage is secured by the slowly inter- 

 crossing marginal spikes, which act like 

 the large meshes of a fishing-net, allowing 

 the small and useless fry to escape. 

 DARWIN Insectivorous Plants, ch. 13, p. 252. 

 (A., 1900.) 



3578. UTILITY, ENDEAVOR TO AT- 

 TAIN Magnetism Converted into Electricity- 

 Faraday's Words. Faraday's reply to those 



who saw nothing gained by the development 

 of the little [electric] spark, and who de- 

 manded its utility, was . . . sententious. 

 " Endeavor to make it useful," he said. He 

 left to others the immediate work of doing 

 so. Some twenty-five years later he saw 

 that tiny flash expanded into the magnifi- 

 cent blaze of the famous South Foreland 

 lighthouse. To-day it illuminates the thor- 

 oughfares of the great cities of the civilized 

 world. PARK BENJAMIN Age of Electricity, 

 ch. 7, p. 90. (S., 1897.) 



3579. UTILITY, HIGHER AND LOW- 

 ER Knowledge for the Sake of Man Means 

 Valued in Proportion to End. There are 

 few, I believe, disposed to question the specu- 

 lative dignity of mental science; but its 

 practical utility is not unfrequently denied. 

 To what, it is asked, is the science of mind 

 conducive? What are its uses? I am not 

 one of those who think that the importance 

 of a study is sufficiently established when 

 its dignity is admitted; for, holding that 

 knowledge is for the sake of man, and not 

 man for the sake of knowledge, it is neces- 

 sary, in order to vindicate its value, that 

 every science should be able to show what 

 are the advantages which it promises to con- 

 fer upon its student. I, therefore, profess 

 myself a utilitarian; and it is only on the 

 special ground of its utility that I would 

 claim for the philosophy of mind what I 

 regard as its peculiar and preeminent im- 

 portance. HAMILTON Metaphysics^ lect. 1, 

 p. 3. (G. & L., 1859.) 



3580. UTILITY MORE THAN 

 BEAUTY Classic Lamps The Argand Burn- 

 er. The Greek and Roman lamps, tho in 

 beautiful receptacles of bronze or silver, 

 were exactly the same in principle as those 

 of the lowest savage, and hardly better in 

 light-giving power ; and tho various improve- 

 ments in form were introduced, the first 

 really important advance was made by the 

 Argand burner. This introduced a current 

 of air into the center of the flame as well 

 as outside it, and, by means of a glass chim- 

 ney, a regular supply of air was kept up, 

 and a steady light produced. Altho the in- 

 vention was made at the end of the last 

 century, the lamps were not sufficiently im- 

 proved and cheapened to come into use till 

 about 1830; and from that time onward 

 many other improvements were made, chiefly 

 dependent on the use of the cheap mineral 

 oils, rendering lamps so inexpensive, and 

 producing so good a light that they are now 

 found in the poorest cottages. WALLACE 

 The Wonderful Century, ch. 4, p. 28. (D. 

 M. & Co., 1898.) 



3581 . UTILITY NOT THE SUPREME 



TEST Life a Power beyond Man's Measure of 

 Use. After all, is this question of " use " 

 really one which need concern us greatly in 

 our studies of life? I trow not; for it 

 surely indicates by no means a lofty con- 

 ception of things if we are perpetually to 



