AC.RKl'LTrRAL APPFIOPKIATION BIM>, 1024. 89 



oltsrrviit ions with kit«'S aiul llial takes foiii- to liv«' ln»iiis «'atli day. 

 and two ohst'fvat i<tiis with |iil<it hnlNioiis i-n li ihiv. ;ih«iiif ■.m hmir 

 and 11 hnlf emit. 



I may sny, as to the tiiiu> consiiiiird, that it takrs a ;;ood dral of 

 tiinr to coinpnto or fediicp the infofiiiation to a point whoiT it is 

 llsahK'. T\\v Ihmii- and a lialf icft-iicd to is consniiifd in tjdcinir ti»o 

 observations. 



Mr. ANnKKsjix. On an aN*'!"a;;»', how hi^h (h) tlit's*- halloons and 

 kit»'s <;o^ 



Mr. (iHK«j<j. On an av»'ra;;»' kites ascend to ahoiit l\ or '2 niih'.s: 

 oecasionally H or 4 miles. TiaIh>ons <ro up on an avera;r«' I shouhl 

 say 2\ or .'? mih's, hut occasiomillv as hi^rh as 10 or L") miles. Of 

 e«)urse the hei<.rl»t reached de|)en(ls entirely npon the .state of the 

 sky. 



KKHUI.TS OK OBSKKV.VTIONS. 



Mr. .Vndkr.sox. From the.se observations are yon able to predict 

 the condition of the atmosphere with respect to storms, wind vel<K'- 

 ity and all that sort of thinir in the upper airf 



Mr. (iRK<;f:. That is the primary pnrpf)se of the observation. I 

 mi<rht sav that all these observations are sent to forecastin<r centers 

 at Washin«rton. Chica<r<) and San F'rancisro. and forecasts for the 

 14 zones into whicji the country is divided are made and sent out 

 twice daily i)y radio. 



Mr. ANnKu.sox, Apparently all this has direct relationship to 

 your daily forecastinjr. What relation has it to research and in- 

 vestijrJition and ]>ro<rress in meteorolojjical science in <reneraH 



Mr. Marvin. Tliat is a matter I wanted to emphasize just before 

 I asked Mr. (xreofjr to tell ai)out the stations. The free air observa- 

 tions have <rreat value and these publications are e.\anii)les of the 

 uses made of them in the study of upper air problems. This service 

 for aviation is only one of the uses of the aerolojrical work. The 

 data have a very important bearinjr upon the phenomena of the cir- 

 culation of the air out of which knowledo:e we hope to be able to 

 improve our knowledjre of tlie laws of forecastinff. 



Mr. Hi ciiANAX. Mow deep is the atmosphere^ How hi«rh ^ 



Mr. ^^ARVI^^ The hiofhest points are perhaps three or four hun- 

 dred miles in the atmosphere where meteors become luminous, when 

 they penetrate the outermost j>ortions of the atmospiiere. 



^Ir. Hi ciiANAN. 1 thoiijrht they knew ai)S()lutelv the hei«;ht of 

 the atmosphere. 



.Mr. Marvin. Well, no: it goes on and on. more and more attenu- 

 ate<l. 



Mr. Buchanan. Is not there any limit to it out there — any limit 

 to where the air extends^ 



Mr. Marvin. Oh, no: not exactly. It has no definite outer l»<)und- 

 ary. It is all within three or four hundred miles. This report on 

 u[)per air pressure maps is one of the studies that has jjeen made of 

 the free air data in the lower layers. It is one of the most import- 

 ant contributions to this science and deals with reducin«r pressure 

 oi)s*'rvation upward instead of reducing them to sea level, which is 

 the ordinary practice. 



