Page:Science vol. 5.djvu/105

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��_ the Isthmus of Paimiiiu was ouly one half- Jnch, and the elevation or the railroad less tlian one-twentietti of an incli. Again: the moun- tain of Santa Marts, ne.ir Cartagena, was 17.000 feet, or nearly three inches in hciglit; Imt the whole gave rel.">tive heights which conid have heen Bhoivn in no other way.

.). K. Bartlett.

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^ta tiK

Mr.

��THE BALLOON IN METEOROLOGY.

��Os the afternoon of Jan. 19 the first bal- loon asc«nt ever made in this coiinlrj- solely i the interest of raeteorology took place at Sliltidelphia. As the b^inning of a series to ^carried out strictly I'or scieotifio piir|>09es, it t an event of no small importance. Gen- I, chief Big nal-ofBcer. U.S.A., rcct^izing the importance nnd vahie of a more complete knowledge of the upper atmosphere, entered into a contract some time ago with the well- known aeronaut, Mr. .S. A. King, for a num- ber of ' trips to the clouds,' an ascent to be made at any time on eight hoars' notice. Although llie first balloon excursion for clly scientific iiurposes made in America, was by no means the first on record. Luraliy. very soon after the invention of the loon, attempts were made to utilize it in me- rolo^cal investigations. Doubtless, the first intB having this end in view were made by Robinson, from St. Petersburg, at the mmand of the emperor of Russia, in 1803 and 1904; but it does not appear that any im- porUot results came from them. On Aug. 31,

1804, Gay-Lussac and Biot made an ascent.

lobing a height of thirteen thousand feet;

' meteorological observations wei*e com-

tooed after an elevation of seven thousand

t had been passed. On Sept. 1;') of the

same year, Gay-Lussac reached a height of

twenty-thi-ee thousand feet, making a series of

most important observations, mid bringing air

mn from that height, which, on being ana-

1, was found to hare the same constitution

l^tbat at the surface.

Wifol much seems to have been done from Biai time until 1843, when the British associa- tion for the advancement of science appointed a committee and voted a sum of money for the purpose of espiTimenting with captive bnl-

K. Although the work wascontinued under ol committees, it was not very successful. [. doubtless, to a lack of efcill in the man- ent of captive balloons. In 1650 Messrs. and linrrnl made ascents in France for the

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��purpo^ieof uieleoi'ologica! study, in which it was planned to asi-i'uil to heights as great as forty thousand foot. They did not succeed, however. in reaching greater elevations than had been attained before, but obtained results verifying in the main those of Gay-Lussac. On one of these excursions an elevation of twenty-three thouBand feet was reached; and, in addition to the meteorological work, interesting observa- tions were made on polarization and other opti-

A aeries of ver\' ini]>ortaut ascents was made by Mr. Welsh of the Kew observatory in August, October, and November of 1852. in which heights varying from twehe thousand feet to twenty-three thousand feet were reached.

A low years later the interest of the British association in the subject was renewed, and culminated in the celebrated series of ascents made bj' Mr. Glaisher, the first being on July 1 7, lS(i2. In these ascents the most complete arrangements were made for the study of the physics of the higher atmosphci'e, and they were remarkably successRil.

Since that time, scientific ballooning has been carried on with great success in France by Camille Flammarion, W, De Fonvtlle. and Gaston Tissandier. A complete and estremel.v interesting history of their work (up to the date of its issue), together with that of Glaisher, is to be fotmd in a volume entitlini ' Travels in the air,' by James Glaisher.

The U- S. signal-service has had this subject under consideration for several years. Pro- fessor Abbe began in 1871 to collect meteoro- logical records made in balloons. In 1872 the records of fifty ascents had been tabulated, studied, and valuable results obtained. In 187 one thousand small balloons were sent with the Polaris e\pe<]ition. to be used in determining the height of the clouds: but, owing to an imfortunatc accident, they could not be utilized. At various times the chief signal-ofHcer lias sent observers on balloon I'scui'sions which were made for purposes other than scientific.

The considerable certainty with which the movement of a storm can now be predicted renders it possible and desirable to make sys- tematic use of the balloon in the study of unusual atmospheric conditions, and the series of ascents just begun is planned with that end in view. Among other things, it is desired to determine the ditfeience in the temperature gradient in well-defined ' high ' and well-defined ■ low ' pressures. For this purpose it is neces- sary to foretell the arrival of a particular .itmospheric condition at Philadelphia, from

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