235 



SCIENTIFIC SIDE-LIGHTS 



Expenditure 

 Experiment 



torn. This fact was verified by carefully 

 fixing a great number of marks in the ice, 

 arranged in a straight line, which gradually 

 assumed a beautiful curve, the middle part 

 pointing down the glacier, and showing a 

 velocity there double or treble that of the 

 lateral parts. He ascertained that the rate 

 of advance by night was nearly the same as 

 by day, and that even the hourly march of 

 the icy stream could be detected, altho the 

 progress might not amount to more than six 

 or seven inches in twelve hours. By the in- 

 cessant tho invisible advance of the marks 

 placed on the ice, " time," says Mr. Forbes, 

 " was marked out as by a shadow on a dial, 

 and the unequivocal evidence which I ob- 

 tained, that even while walking on a glacier 

 we are, day by day, and hour by hour, im- 

 perceptibly carried on by the resistless flow 

 of the icy stream, filled me with admira- 

 tion." LYELL Geology, ch. 15, p. 224. (A., 

 1854.) 



1 145. EXPERIMENT CONFIRMS THE- 

 ORY Galileo with Telescope Verifies Reason- 

 ings of Copernicus Jupiter with His Satel- 

 lites a Little Universe. In 1609 Galileo con- 

 structed his telescope, and very soon discov- 

 ered the satellites of Jupiter. This at once 

 confirmed the Copernican theory, by opening 

 before the eyes of men another system, 

 subordinate to the solar, of heavenly bodies 

 revolving about their primaries, thus giving 

 an analogon of the greater. The subsequent 

 discovery by the same instrument of the 

 phases of Venus at once confirmed the new 

 theory of the revolution of the planets about 

 the sun, and answered an objection against 

 it by explaining why Venus did not appear 

 larger when nearer the beholder. Coperni- 

 cus furnished the suggestion by reflecting on 

 the known fact that the apparent places of 

 objects may be accounted for by the motion 

 of one or both, and that the solution or the- 

 ory which w*as the simplest was to be pre- 

 ferred. Galileo, by his telescope, prepared 

 the way for the experiment by enabling ob- 

 servers, in a certain sense, to observe for 

 themselves which moved the sun or the 

 earth. PORTER Human Intellect, pt. iii, ch. 

 8, p. 477. (S., 1899.) 



1146. Insectivorous Plants 



"Fed" and "Starved" Rapid Growth 

 Due to Animal Food. Since the publica- 

 tion of the first edition, several experiments 

 have been made to determine whether in- 

 sectivorous plants are able to profit by an 

 animal diet. 



My experiments were published in Lin- 

 nean Society's Journal, and almost simul- 

 taneously the results of Kellermann and 

 Von Raumer were given in the Botanische 

 Zeitung. My experiments were begun in 

 June, 1877, when the plants were collected 

 and planted in six ordinary soup-plates. 

 Each plate was divided by a low partition 

 into two sets, and the least flourishing half 

 of each culture was selected to be " fed," 

 while the rest of the plants were destined to 



Weight (without flower-stems) . . 



Number of flower-stems , 



Weight of stems 



Number of capsules 



Total calculated weight of seed. . , 

 Total calculated number of seeds 



be " starved." The plants were prevented 

 from catching insects for themselves by 

 means of a covering of fine gauze, so that 

 the only animal food which they obtained 

 was supplied in very minute pieces of roast 

 meat given to the " fed " plants, but with- 

 held from the " starved " ones. After only 

 ten days the difference between the " fed " 

 and " starved " plants was clearly visible : 

 the fed plants were of brighter green, and 

 the tentacles of a more lively red. At the 

 end of August the plants were compared by 

 number, weight, and measurement, with the 

 following striking results : 



Starved. Fed. 

 100 121.5 

 100 164.9 

 100 231.9 

 100 194.4 

 100 379.7 

 100 241.5 



DARWIN Insectivorous Plants (addition by 

 FRANCIS DARWIN), ch. 1, p. 15. (A., 1900.) 



1147. Scientific Assur- 

 ance Fulfilled. By way of experiment, the 

 sinking of a well was commenced at Paris 

 in 1834, which had reached, in November, 

 1839, a depth of more than 1,600 English 

 feet, and yet no water ascended to the sur- 

 face. The government were persuaded by M. 

 Arago to persevere, if necessary, to the 

 depth of more than 2,000 feet; but when 

 they had descended above 1,800 English 

 feet below the surface, the water rose 

 through the tube (which was about ten 

 inches in diameter j , so as to discharge half a 

 million of gallons of limpid water every 

 twenty-four hours. The temperature of the 

 water increased at the rate of 1 8' F. for 

 every 101 English feet as they went down, 

 the result agreeing very closely with the 

 anticipations of the scientific advisers of 

 this most spirited undertaking. LYELL 

 Principles of Geology, bk. ii, ch. 16, p. 234. 

 (A., 1854.) 



1148. EXPERIMENT NECESSARY 

 FOR THE FULL DEVELOPMENT OF A 

 SCIENCE What the Ancients Knew of Light. 

 But other objects than the motions of the 

 stars attracted the attention of the ancient 

 world. Light was a familiar phenomenon, 

 and from the earliest times we find men's 

 minds busy with the attempt to render some 

 account of it. But without experiment, 

 which belongs to a later stage of scientific 

 development, little progress could be made 

 in this subject. The ancients, accordingly, 

 were far less successful in dealing with light 

 than in dealing with solar and stellar mo- 

 tions. Still they did make some progress. 

 They satisfied themselves that light moved 

 in straight lines; they knew also that light 

 was reflected from polished surfaces, and 

 that the angle of incidence of the rays of 

 light was equal to the angle of reflection. 

 These two results of ancient scientific curi- 

 osity constitute the starting-point of [mod- 

 ern scientific knowledge on the subject]. 

 TYNDALL Lectures on Light, lect. i, p. 5. 

 (A., 1898.) 



