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THE POPULAR SCIENCE MONTHLY. 



tions investigation of the ray of light that 

 has passed through it by spectroscopic ex- 

 amination and by observations of the twin- 

 kling of the stars and of the fluctuations on 

 the margins of the larger celestial bodies 

 when viewed in the telescope. The infor- 

 mation obtained in these ways must, how- 

 ever, always be vague, because the total re- 

 sult received by us is the integration of the 

 individual effects at each point of the path, 

 and it is not practicable to separate the sum 

 into its parts ; while the knowledge ob- 

 tained would be otherwise incomplete. Other 

 means of systematic exploration of the free 

 air are by towers, like the Eiffel Tower in 

 Paris, kites, pilot balloons (without aero- 

 nauts), and balloons carrying aeronauts. 

 Towers do not reach to the height it is de- 

 sired to explore. The method by kites has 

 been studied especially by Mr. William A. 

 Eddy, of Bergen Point, N. J. Mr. Eddy 

 uses tailless kites, placing them in tandem, 

 and recommends that they be flown in 

 groups of three. By such means he has at- 

 tained heights of between four thousand and 

 five thousand feet, and expects to reach 

 fourteen thousand feet without great diffi- 

 culty. Three tailless kites will fly when any 

 one of the three will not in mild surface 

 winds. They easily right themselves when 

 reversed, and a tandem series of kites tends 

 to prevent the jerking which might put the 

 instruments out of order. The best possi-' 

 ble anemometer is a balloon which is im- 

 mersed in the air and moves freely with it. 

 While such balloons can be employed only 

 for the study of air currents, by a proper 

 selection of places and dates and the assist- 

 ance temporarily of theodolites and persons 

 capable of working with them they could be 

 made very useful. They would enable us to 

 study the arrangement of air currents about 

 definite meteorological phenomena, such as 

 centers of high or low pressure. A more 

 instructive but more expensive method is 

 that of pilot balloons carrying automatic 

 registering instruments. Balloons sent up 

 by M. Hermite in 1892 carried means for the 

 automatic record of pressure and tempera- 

 ture, but were disabled from registering the 

 temperature by the cold stiffening the ink. 

 They also carried a device for releasing and 

 dropping cards for tracing the course of the 

 balloon, which did not operate very satisfac- 



torily. Much better service than this would 

 be given by systematic work by a meteorolo- 

 gist who would make the ascension himself. 

 Evidence points to the conclusion that the 

 cloud layer and perhaps the upper cloud 

 service is a region of especial activity in 

 meteorological phenomena, but the facts on 

 which such a conclusion could be verified 

 are of such character that they would proba- 

 bly escape any automatic registry. Prof. 

 Harrington furnishes estimates showing that 

 the cost of operating any of these methods 

 could be brought within reasonable limits. 



Telpherage Lines. The telpherage meth- 

 od of transportation is much better known 

 in Spain, Italy, and the British colonies than 

 in England and the United States. Its 

 history may be hypothetically traced as an 

 evolution from the single-rope bridges of the 

 Himalayas and Thibet cables made of 

 twisted birch twigs on which the passenger 

 crosses seated in a hoop, which he hitches 

 forward while he holds the rope above with 

 his hands. The next development is to 

 fasten a cord to the hoop by which it is 

 drawn to either side. A similar rough form 

 of transport, except that buckets and wheels 

 were used instead of the hoop, was employed 

 for many years in the lead mines of the 

 Peak of Derbyshire. A great impulse was 

 given to the method by the invention of 

 twisted steel cables, which made the lines 

 stronger and more lasting. More than two 

 thousand miles of telpher line are now in 

 working order in Spain, Italy, South Amer- 

 ica, India, Cape Colony, China, and Japan. 

 A line at Hong Kong, rising ten hundred and 

 ninety feet in two miles, is used for the 

 transportation of the European workmen at 

 the port up the mountain at night, in order 

 that they may sleep in purer air. It is led 

 straight up the mountain side on high steel 

 trestles, and carries, in little back-to-back 

 cars, three persons on each side. At Table 

 Mountain, Cape Colony, the suspending wire 

 is carried in a single span fourteen hundred 

 and seventy feet to the edge of the cliff, and 

 thence in another span fourteen hundred 

 feet to the top of the mountain. At the Rock 

 of Gibraltar the wire runs, after a first leap 

 of eleven hundred feet, straight to the sum- 

 mit on a series of lofty trestles in an ascent 

 of one foot to every foot and a half. At 



