428 



THE POPULAR SCIENCE MONTHLY. 



expenditure of 2,500,000,000 pounds of en- 

 ergy. Assuming that an area of 100 miles 

 square with a mean depth of one mile was 

 thus in vibration at any one instant of time 

 — which is not improbable, considering the 

 known rate of transmission and the long 

 duration of the earthquake — the amount of 

 energy thus represented would be 25X10"12 

 foot-pounds. This energy might be gen- 

 erated by the fall under the action of grav- 

 ity of a cube of rock 1,000 feet on each edge, 

 the mass of which would be '75,000,000 

 tons, through a vertical distance of 166 

 feet." Also, assuming certain magnitudes, 

 "I find the energy of a cubic mile of the 

 Charleston earthquake, taken near enough 

 to the epicentrum to be disturbed as above 

 assumed, to be equal to 2-1,000,000,000 foot- 

 pounds. The speed of transmission of this 

 disturbance has been pretty well determined 

 by Newcomb and Sutton to be approxi- 

 mately three miles per second, so that a 

 cubic mile would be distributed in one third 

 of a second. To do this would require 

 130,000,000 horse-power. Assuming that 

 an area about the epicentrum 100 miles 

 square was thus disturbed, the energy would 

 be that of 24X10-13 foot-pounds, and the 

 rate of its expenditure would be that of 

 1,300,000,000,000 horse-power." 



Gems. — The diamond became generally 

 employed as a finished gem in France during 

 the first quarter of the fifteenth century. The 

 art of cutting it has gradually improved and 

 developed, until now, two million five hun- 

 dred thousand carats of diamonds are annu- 

 ally cut in Amsterdam. The principal source 

 of supply has shifted from India to Brazil, 

 and now to South Africa, whose Cape dia- 

 monds at present furnish ninety-five per 

 cent of European supply. The quality of 

 these diamonds, according to Mr. Alfred 

 Phillips, has been purposely underestimated 

 by interested parties. It is true that color- 

 less diamonds have been found in the small- 

 est proportions in South Africa, but it is 

 equally beyond dispute that large numbers 

 of the whitest and most faultless diamonds 

 are exported from the Cape, while the mass 

 of the material is conspicuous, whether white 

 or colored, for its brilliancy. The ruby is 

 next highest in value, and after it comss the 

 sapphire, which is only another colored ruby. 



Although the cheapest of the major gems, 

 its loss, according to Mr. Phillips, would be, 

 on account of its intrinsic value and unri- 

 valed blue color, a greater misfortune to 

 the art-goldsmith than that of either the 

 ruby or the emerald. The emerald is one of 

 the most beautiful, although the softest, of 

 the precious gems, and is easily fusible with 

 borax into a colorless glass. The true em- 

 erald occurs in crystals seldom over one inch 

 in length. The so-called Oriental emerald 

 of India is not an emerald, but a green ruby 

 or sapphire. The exquisite tones peculiar 

 to the minor gems, or those of lesser value, 

 establish them as a separate category when 

 compared with the magnificent or acknowl- 

 edged gems. Among them the amethyst 

 was worn in the middle ages as an amulet 

 and preservative in battle, and was distin- 

 guished as a pious or episcopal gem, figur- 

 ing wherever it was desirable to impart se- 

 rious beauty or dignity to the property of 

 the church, Then we have the chrysolites, 

 the topazes of various hues, and the garnets. 

 Oriental varieties of which ranked with gems 

 of a higher order rather more than a century 

 ago. The opal was held in the highest re- 

 pute in ancient times, first for its beauty, 

 and then because its own mythology consti- 

 tuted it a harbinger of love and good-v,ill. 

 It has lost in value in modern times, through 

 the influence of a silly superstition. The 

 selenite, or moonstone, is a gem of great beau- 

 ty, and admits of a great vai'iety of applica- 

 tions, on account of the softness of its tint, 

 which enables colored gems, diamonds, and 

 enamels to be agreeably associated with it. 



About a Crocodile. — " Ubique " (Parker 

 Giilmore) tells, in " Land and Water," of a 

 crocodile which he saw in Java almost sev- 

 enteen feet long. " It frequented the vicinity 

 of a place where the village women were in 

 the habit of assembling to wash their clothes, 

 and, if report spoke truly, many were the 

 Malay females it had carried off. At length 

 it was captured by using a live dog for bait. 

 After being transferred from its watery 

 home to the commandant's garden, it was 

 safely secured upon the lawn by innumer- 

 able moorings. Our assistant surgeon ad- 

 ministered the saurian an immense dose of 

 strychnine, enough, as he said, to poison a 

 regiment, but it had not the slightest injuri- 



