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POPULAR SCIEIS'CE ITEWS. 



[July, 1889. 



In an experiment shown by Mr. Shelford Bidwell, 

 a bar of iron, which has undergone certain prelimi- 

 nary treatment, is placed close to a small reflecting 

 magnetometer. When the iron is illimiinated by 

 an oxyhydrogen lamp, it instantly deflects the mag- 

 netometer needle, as is evidenced by the movement 

 of the spot of light upon the scale ; and when the 

 illumination is cut off, the spot of light at once goes 

 back. The preparation of the iron consists in iirst 

 magnetizing it by a current of electricity passed 

 through a surrounding coil, and then very perfectly 

 demagnetizing it by a reversed current of suitable 

 strength. Its magnetic condition is thus rendered 

 unstable, and its susceptibility appears to be greater 

 for a small magnetizing force acting in the same di- 

 rection as that by which the bar was at first mag- 

 netized than for an equal small force in the opposite 

 direction. In the experiment the end of the iron 

 rod was about half an inch from the end of the sus- 

 pended magnetometer needle; .the bar of iron was 6 

 inches long and 'A inch in diameter. The whole of 

 the bar was illuminated to produce the deflection. 

 The instrument was so sensitive that it was affected 

 by the iron in the wheels of cabs moving in the 

 court yard outside ; the disturbance was not due to 

 the vibrations of the ground set up by the cabs. 



Mr. J. W. Swan exhibited a Gramme ring, rotat- 

 ing under the influence of the magnetism of the 

 earth. Within a shallow circular brass box, about 

 five inches in diameter, twenty little coils of insulated 

 wire were disposed near the circumference; each 

 coil consisted of 400 turns of wire, making 8,000 

 turns altogether. The resistance of the coil when 

 the current was split was forty or fifty ohms, the 

 current passing in the ring was about half an 

 ampere. This ring was free to turn on a vertical 

 pivot, and continued to turn steadily, under the in- 

 fluence of the magnetism of the earth. 



Mr. II. Brereton Baker performed some curious 

 experiments, as follows, on non-combustion in dried 

 oxygen : i . Charcoal was heated to redness in 

 dried oxygen without any visible combustion. The 

 oxygen had been in contact with the drying agent 

 for two months. 2. Sulphur was distilled in oxy- 

 gen dried by phosphorus pentoxide for five years; 

 no flame was seen. In moist oxygen, sulphur burns 

 at a temperature of 320°; its boiling point is 440°. 

 3. Phosphorus was distilled in o.xygen dried in the 

 same way; in boils at 290°. In moist oxygen it 

 catches fire at about 60°. 4. Ordinary phosphorus, 

 he said, is not luminous at any pressure in dried 

 oxygen. 



Captain H. Capel L. Ilolden exhibited a chrono- 

 graph for measuring the velocity of projectiles and 

 small periods of time. Mr. William Crookes ex- 

 hibited a great photographic map of the solar spec- 

 trum, taken by means of a Rowland's grating. Mr. 

 C, V. Boys exhibited some useful applications of 

 fibers of quartz. Professor J. W. Judd exhibited 

 specimens of Egyptian blue recently made by Pro- 

 fessor Fouque, who discovered the ancient coloring 

 matter to consist chiefly of silicate of lime and sili- 

 cate of copper. Mr. Killingworth Hedges exhibited 

 an automatic safety device for use in connection 

 with electric light circuits when alternating current 

 transformers are employed. — Scientific American. 

 *»► 



WHY SIXTY SECONDS MAKE A MINUTE. 

 Why is our hour divided into 60 minutes, each 

 minute into 60 seconds, etc. .'' Simply and solely 

 because in Babylon there existed, by the side of the 

 decimal system of notation, another system, the 

 sexagesimal, which counted by sixties. Why that 

 number should have been chosen is clear enough, 

 and it speaks well for the practical sense of those 

 ancient Babylonian merchants. There is no num- 

 ber which has so many divisorB as 60. The Baby- 



lonians divided the sun's daily journey into 24 para- 

 sangs, or 710 stadia. Each parasang or hour was 

 subdivided into 60 minutes. A parasang is about a 

 German mile, and Babylonian astronomers com- 

 pared the progress made by the sun during one 

 hour at the time of the equinox to the progress 

 made by a good walker during the same time, both 

 accomplishing one parasang. The whole course of 

 the sun during the 24 equinoctial hours was fixed at 

 24 parasangs, or 720 stadia, or 360 degrees. This 

 system Avas handed on to the Greeks, and Ilippar- 

 chus, the great Greek philosopher, who lived about 

 150 B. C. introduced the Babylonian hour into 

 Europe. Ptolemy, who wrote about 140 A. D., and 

 whose name still lives in that of the Ptolemaic sys- 

 tem of astronomy, gave still wider currency to the 

 Babylonian way of reckoning time. It was carried 

 along on the quiet stream of traditional knowledge 

 through the Middle Ages, and. strange to say, it 

 sailed down safely over the Niagara of the French 

 Revolution. For the French, when revolutionizing 

 weights, measures, coins, and dates, and subjecting 

 all to the decimal system of reckoning, were in- 

 duced by some unexplained motive to respect our 

 clocks and watches, and allowed our dials 

 to remain sexagesimal, that is, Babvlonian, 

 each hour consisting of 60 minutes. Here you see 

 again the wonderful coherence of the world, and 

 how what we call knowledge is the result of an un- 

 broken tradition of a teaching descending from 

 father to son. Not more than about a hundred 

 arms would reach from us to the builders of the pal- 

 aces of Babylon, and enable us to shake hands with 

 the founders of the oldest pyramids and to thank 

 them for what they have done for us. — Max Muller. 

 in the Fortnicjhtly Review. 



CAVE-DWELLERS IN MEXICO. 



A DI.SPATCII from Deming, New Mexico, says : 

 "Lieutenant Schwatka has arrived here. His party 

 has been successful beyond expectations in their ex- 

 plorations, and especially in southern Chihuahua, 

 where living cliff and cave-dwellers were found in 

 great abundance, wild as any of the Mexican tribes 

 at the time of Cortez's conquest. The abodes they 

 live in are exactly similar to the old, abandoned 

 cliff-dwellings of Arizona and New Mexico, about 

 which there has been much speculation. It was 

 almost impossible to get near them, so wild and 

 timid wert they. Upon the approach of white peo- 

 ple they fly to their caves by notched sticks placed 

 against the face of the cliffs, if too steep, although 

 they can ascend vertical stone faces, if there are the 

 slightest crevices for fingers and toes. 



"These cliff-dwellers are sun-worshipers, putting 

 their new-born children out in the full rays of the 

 sun the first day of their lives, and showing many 

 other forms of devotion to the great luminary. 

 They are usually tall, lean and well-foi-med, their 

 skin being a blackish red, much nearer the color of 

 the negro than the copper-colored Indian of the 

 United States. 



"Schwatka claims that nothing has heretofore 

 been known about these people, except by the half- 

 Indian mountain Mexicans, and thinks his investi- 

 gation will be of immense anthropological and 

 archaeological value. He estimates the cave and 

 clift-dwellers to be from 3,000 to 12,000 in number, 

 armed only with bows, arrows and stone hatchets." 



SCIENTIFIC BREVITIES. 

 The Common Harebell {Campanula rotundi- 

 folia), although of a deep blue color, often turns 

 white in the process of drying for the herbarium. 

 There is, however, a white variety, and a most curi- 

 ous fact is, that the flowers of this variety turn blue 

 in drying. 



Chameleon-like Spiders. — All observant peo- 

 ple must have seen the yellow spiders on yellow 

 flowers, and white spiders on white flowers, that 

 catch bees and other insects which visit the flowers 

 — not noticing their enemies because of their decep- 

 tive coloring. These spiders live by their looks, 

 and never go to the trouble of spinning a web. 

 James Angus considers that these white and yellow 

 spiders belong to the same species, and that they 

 can change their color according to the flower they 

 select. 



Hot Iron and Cold Water. — If a ladle of iron 

 is accidentally spilled it will, of course, almost inev- 

 itably do some damage or injure some one. But 

 the chances for the man getting away from it are 

 fairly good unless water is encountered, when there 

 is immediately such a violent explosion and scatter- 

 ing of hot metal that there is very little chance for 

 the escape of any one without injury. A combina- 

 tion of melted iron and water is as dangerous as 

 gunpowder, and iron-workers should always take 

 pains to prevent such a combination being possible. 



Relics of the Iron Age in Norway. — Recently 

 there have been some valuable "finds" of antiquities 

 belonging to tlie iron age in Norway. At Nottero, 

 on the Christiania Fjord, there were found in a 

 mound some bones, an iron pot with handles, a 

 sword two feet six inches long, the handle having 

 knobs of a yellow metal, an anvil, and a pair of 

 smith's tongs. The mound, Nature says, was no 

 doubt at one time situated close to the sea; it is 

 now some three hundred yards inland. At Laurvig 

 a large number of similar articles were discovered in 

 two mounds. 



Du.sT Particles in the Air. — xVn ingenious 

 method has been devised by Mr. John Aitken for 

 counting the dust particles in the atmosphere. It 

 was found that when the moisture is condensed in a 

 rarefied atn\osphere, each raindrop has a dust particle 

 for its nucleus, so that by sweeping a measured por- 

 tion of the air into an exhausted receiver, by means 

 of pure air, and counting the number of deposited 

 drops, it is easy to calculate the number of dust par- 

 ticles in a given volume of the impure air. The 

 counting is managed by having the silver plate in 

 the receiver divided into millimetre squares, so that 

 it is only necessary to count the drops on one square 

 millimetre. Mr. Aitken showed that the air of a 

 hall contained 400,000 particles to the cubic centi- 

 metre, while a specimen of air taken near the roof of 

 the hall gave 3,500,000 to the cubic centimetre. In 

 Edinburgh, on a fine day after snow, the number of 

 dust particles in the cubic centimetre was 75,000, 

 but in pure country air the number is often as low 

 as 5,000. 



A Very Curious Race, possessing no little in- 

 terest for students of natural history, and which is 

 vouched for by our English contemporary Knowledge, 

 was recently witnessed in Westphalia, the contest 

 being between pigeons and a number of bees, the 

 respective owners of which had wagered their favor- 

 ites to win. The course was three miles and a half, 

 that being the distance between the two villages of 

 Rhynern and Hamme ; and a dovecot which hap- 

 pened to be near a hive was selected as the winning- 

 post. It was found no easy matter to mark the bees 

 so as to make their identity unmistakable, but the 

 difficulty was at last surmounted by rolling them in 

 flour previous to starting them on their journev. 

 This, while making them easily recognized on their 

 arrival, probably retarded their flight; but, never- 

 theless, and though the pigeons were looked upon 

 by those interested as the most likely winners, the 

 race resulted in a victory for the bees; the first bee 

 arriving at the post twenty-five seconds before the 

 first pigeon, and three other bees before the second. 



