itch 



lanet 



SCIENTIFIC SIDE-LIGHTS 



528 



2604. PITCH LAKE OF TRINIDAD 



Dead Forests Decomposed by Volcanic Fires. 

 Fluid bitumen is seen to ooze from the 

 bottom of the sea on both sides of the island 

 of Trinidad, and to rise up to the surface of 

 the water. Near Cape La Braye there is a 

 vortex which, in stormy weather, according 

 to Captain Mallet, gushes out, raising the 

 water five or six feet, and covers the surface 

 for a considerable space with petroleum or 

 tar; and the same author quotes Gumilla as 

 stating, in his " Description of the Orinoco," 

 that about seventy years ago a spot of land 

 on the western coast of Trinidad, near half- 

 way between the capital and an Indian vil- 

 lage, sank suddenly and was immediately 

 replaced by a small lake of pitch, to the 

 great terror of the inhabitants. 



It is probable that the great pitch lake 

 of Trinidad owes its origin to a similar 

 cause; and Dr. Nugent has justly remarked 

 that in that district all the circumstances 

 are now combined from which deposits of 

 pitch may have originated. The Orinoco has 

 for ages been rolling down great quantities 

 of woody and vegetable bodies into the sur- 

 rounding sea, where, by the influence of 

 currents and eddies, they may be arrested 

 and accumulated in particular places. The 

 frequent occurrence of earthquakes and other 

 indications of volcanic action in those parts 

 lend countenance to the opinion that these 

 vegetable substances may have undergone, 

 by the agency of subterranean fire, those 

 transformations and chemical changes which 

 produce petroleum; and this may, by the 

 same causes, be forced up to the surface, 

 where, by exposure to the air, it becomes 

 inspissated, and forms the different varie- 

 ties of pure and earthy pitch, or asphaltum, 

 so abundant in the islands. LYELL Prin- 

 ciples of Geology, bk. ii, ch. 16, p. 250. (A., 

 1854.) 



2605. PITILESSNESS OF NATURAL 

 FORCES Contrast with Human Power The 

 Sense of the Sublime. The air [on the Mat- 

 terhorn] was preternaturally still; an oc- 

 casional gust came eddying round the cor- 

 ner of the mountain, but all else seemed 

 strangely rigid and motionless and out of 

 keeping with the beating heart and moving 

 limbs, the life and activity, of man. Those 

 stones and ice have no mercy in them, no 

 sympathy with human adventure; they sub- 

 mit passively to what man can do ; but let 

 him go a step too far, let heart or hand 

 fail, mist gather or sun go down, and they 

 will exact the penalty to the uttermost. 

 The feeling of " the sublime " in such cases 

 depends very much, I -think, on a certain bal- 

 ance between the forces of Nature and man's 

 ability to cope with them: if they are too 

 weak, the scene fails to impress; if they are 

 too strong for him, what was sublime be- 

 comes only terrible. TYNDALL Hours of Ex- 

 ercise in the Alps, ch. 3, p. 44. (A., 1898.) 



2606. PLACE OF BACTERIA IN NA- 

 TURE First Deemed Animals Now Ascer- 



tained To Be Plants Animals Have No 

 Monopoly of Motion. For a considerable 

 period of time after their first detection 

 these unicellular organisms [bacteria] were 

 considered to be members of the animal 

 kingdom. As late as 1838, when Ehrenberg 

 and Dujardin drew up their classification, 

 bacteria were placed among the infusorians. 

 This was in part due to the powers of mo- 

 tion which these observers detected in bac- 

 teria. It is now, of course, recognized that 

 animals have no monopoly of motion. But 

 what, after all, are the differences between 

 animals and vegetables so low down in the 

 scale of life ? Chiefly two : there is a differ- 

 ence in life history (in structure and de- 

 velopment), and there is a difference in 

 diet. ... It is true, they [bacteria] 

 possess motion, are free from chlorophyl, 

 and even feed occasionally upon products of 

 decomposition three physiological charac- 

 ters which would ally them to the animal 

 kingdom. Yet by their structure and cap- 

 sule of cellulose and by their life history 

 and mode of growth they unmistakably pro- 

 claim themselves to be of the vegetable 

 kingdom. In 1853 Cohn arrived at a con- 

 clusion to this effect, and since that date 

 they have become more and more limited in 

 classification and restricted in definition. 

 NEWMAN Bacteria, ch. 1, p. 5. (G. P. P., 

 1899.) 



2607. PLACE OF EXPERIMENTS IN 

 SCIENCE The Investigator Addresses Inquir- 

 ies to Nature The Teacher Presents Her 

 Answers to the Public. Experiments have 

 two great uses a use in discovery and veri- 

 fication, and a use in tuition. They were 

 long ago defined as the investigator's lan- 

 guage addressed to Nature, to which she 

 sends intelligible replies. These replies, 

 however, usually reach the questioner in 

 whispers too feeble for the public ear. But 

 after the discoverer comes the teacher, 

 whose function it is so to exalt and modify 

 the experiments of his predecessor as to ren- 

 der them fit for public presentation. TYN- 

 DALL Lectures on Light, lect. 1, p. 3. (A., 

 1898.) 



2608. PLACE OR PERSON JUMBLED 

 IN MEMORY Accidental Association Light 

 on Some Questions of Veracity. Thus, for 

 example, I may have lent a book to a friend 

 last week. I really remember the act of 

 lending it, but have forgotten the person. 

 But I am not aware of this. The picture of 

 memory has unknowingly to myself been 

 filled up by this unconscious process of 

 shifting and rearrangement, and the idea of 

 another person has by some odd accident 

 got substituted for that of the real bor- 

 rower. If we could go deeply enough into 

 the matter, we should, of course, be able to 

 explain why this particular confusion arose. 

 We might find, for example, that the two 

 persons were associated in my mind by a 

 link of resemblance, or that I had dealings 

 with the other person about the same time. 



