SSiV, 



her 

 teratiou 



SCIENTIFIC SIDE-LIGHTS 



494 



four, while Destutt-Tracy again amplifies 

 it to six. The opinion of the first and last 

 of these philosophers appears to me cor- 

 rect. You can easily make the experiment 

 for yourselves, but you must beware of 

 grouping the objects into classes. If you 

 throw a handful of marbles on the floor you 

 will find it difficult to view at once more 

 than six or seven at most, without con- 

 fusion; but if you group them into twos 

 or threes or fives you can comprehend as 

 many groups as you can units, because the 

 mind considers these groups only as units 

 it views them as wholes, and throws their 

 parts out of consideration. HAMILTON 

 Metaphysics, lect. 14, p. 176. (Sh. & Co., 

 1859.) 



2429. 



Experiments 



show that four and sometimes even five 

 disconnected impressions (letters, numerals, 

 or lines of different direction) may be dis- 

 tinctly perceived. If the separate impres- 

 sions are so arranged that they enter into 

 combination with one another in idea, the 

 number becomes three times as great. Thus 

 we are able to cognize instantly two dis- 

 syllabic words of six letters each. WUNDT 

 Psychology, lect. 16, 2, p. 343. (Son. & 

 Co., 189G.) 



243O. NURSERY, RIMES OF, AS 

 HISTORY Cradle in Tree-top. The first en- 

 gine was run by man-power; then man sub- 

 dued the horse, the ass, the camel, and 

 invented engines for those to propel. He 

 next domesticated the winds, the waters, 

 the steam, the lightning; but the first com- 

 mon carriers and machine-power were men 

 and women. The first burden train was 

 women's backs; the first passenger-car was 

 a papoose- frame. And even now, while I 

 am .speaking to you, more heavy loads are 

 resting on human shoulders than upon all 

 the pack-animals in the world. Hence our 

 nursery rime: 



Rock a by baby on a tree-top, 

 When the wind blows 

 The cradle will rock. 

 When the bou^h bends 

 The cradle will fall. 

 Down will come cradle, 

 And baby and all . 



The poetry of to-day is the fact of yes- 

 terday, the dream of yesterday is the fact of 

 to-day. When the savage woman a century 

 or two ago, upon this very spot, strapped 

 her dusky offspring to a rude frame, hung 

 it upon the nearest sapling for the winds 

 to rock, or lifted the unfortunate suckling 

 from the ground to which it had been hurled 

 by the bending of an unsafe bough, that 

 was a fact, a stage in the history of inven- 

 tion. In our nowadays couches of down, 

 swung from gilded hinges, we have got 

 far ahead of the papoose-cradle, the mem- 

 ory of which we perpetuate in nursery 

 rimes sung to children, who wonder why 

 babies should be hung in the tops of trees, 

 and think, doubtless, that the falling cradle 

 was a just retribution on the silly parents. 



MASON The Birth of Invention (Address 

 at Centenary of American Patent System, 

 Washington, D. C., 1891, Proceedings of the 

 Congress, p. 408). 



2431. NUTRITION, RESPONSE OF 



PLANT TO Rapid Absorption of Nutritious 

 Matter by Sundew Leaf Neglect of Use- 

 less Material. That the glands [of the sun- 

 dew leaf] possess the power of absorption 

 is shown by their almost instantaneously be- 

 coming dark colored when given a minute 

 quantity of carbonate of ammonia, the 

 change of color being chiefly or exclusively 

 due to the rapid aggregation of their con- 

 tents. When certain other fluids are added 

 they become pale colored. Their power of 

 absorption is, however, best shown by the 

 widely different results which follow, from 

 placing drops of various nitrogenous and 

 non-nitrogenous fluids of the same density 

 on the glands of the disk, or on a single 

 marginal gland, and likewise by the very 

 different lengths of time during which the 

 tentacles remain inflected over objects 

 which yield or do not yield soluble nitrog- 

 enous matter. This same conclusion might 

 indeed have been inferred from the struc- 

 ture and movements of the leaves, which 

 are so admirably adapted for capturing in- 

 sects. DARWIN Insectivorous Plants, ch. 1, 

 p. 14. (A., 1900.) 



2432. OAK THE MODEL FOR THE 

 EDDYSTONE The Engineering of Nature. 

 To what example, then, can we look? What 

 better can we wish for than is supplied by 

 that wonderful edifice which, for more than 

 a century, braving the violence of the most 

 destructive storms, has calmly and uninter- 

 mittingly displayed its guiding light to the 

 wave-tossed mariner, and which has fur- 

 nished the pattern of every similar beacon 

 elsewhere erected for the direction and warn- 

 ing of the navigator? I need not tell you 

 to what I refer; for Smeaton and the Eddy- 

 stone are household words to every Briton. 

 . . . It was to Nature, not to the time- 

 honored traditions of his profession, that 

 this great practical philosopher went, when 

 he had to deal with the problem of the Eddy- 

 stone. He saw in the bole of the oak, which 

 had stood the blasts of centuries, the shape 

 that would not only give to his tower the 

 greatest inherent strength, but would pro- 

 ject upwards instead of directly resisting 

 the dash of the impetuous waves. And he 

 then brought all the resources of construc- 

 tive skill to carry out this sagacious design, 

 erecting on a broad and solid founda- 

 tion that beautifully formed superstruc- 

 ture, which not only bears aloft the far- 

 shining and welcome light, but serves as 

 the dwelling-place for those who are charged 

 with its maintenance. CARPENTER Nature 

 and Man, lect. 7, p. 212. (A., 1889.) 



2433. OBJECTION TO NEBULAR 

 HYPOTHESIS Impossible Cohesion Required 

 of Caseous Mass Would Give Meteors In- 



