128 ANNUAL. EEPORTS OF DEPARTMENT OF AGRICULTURE. 



shipping in those waters, which has greatly increased in volume 

 since the opening of the Panama Canal. 



Requests have recently been renewed for the Weather Bureau to 

 increase its contributions of data relating to world meteorology. 

 Further participation in this work, however, must await increase of 

 force. 



INSTRUMENT DIVISION. 



The Instrument Industry. — Conditions during and immediately 

 following the war which made it difficult to obtain instruments from 

 Europe have been followed by the stimulating effect created by de- 

 mands from the Army, Navy, Air Service, and Shipping Board, and 

 from industrial concerns, for meteorological instruments. American 

 manufacturers have hence been justified in undertaking the manu- 

 facture of instruments heretofore largely imported, so that prac- 

 tically all the instruments used by the Weather Bureau are now 

 obtainable in this country. However, clocks for the recording cylin- 

 ders of thermographs and barographs await further development, 

 and there is considerable promise along these lines also. The present 

 tariff schedule requires the various branches of the Government to 

 pay from their appropriations the same import duties as are paid by 

 anyone else; hence there is nO' financial advantage to a bureau in 

 purchasing instriunents abroad, and such conditions are favorable 

 to the upbuilding of a stable and dependable meteorological instru- 

 ment industry in this country. 



The storm-warning display equipment, which was thoroughly over- 

 hauled several years ago, has required little repair, except on the 

 Gulf coast, where changes in organization and the rapid deteriora- 

 tion of ironwork have required a considerable number of replace- 

 ments. The three-lantern system of display, now in satisfactory 

 operation throughout the bureau, has not been found unduly ex- 

 pensive to maintain. 



Exposures of instruments at a number of first-order stations are 

 becoming impaired by the rapidly increasing erection of high office 

 buildings. The problem is not solved by moving the instruments to 

 the higher building. Wliile the wind instruments are given a better 

 exposure by such a removal, the rain-gauge exposure is seriously 

 impaired. Meteorological stations in parks or suburban observa- 

 tories offer the best solution of the problem of securing sound mete- 

 orological data in the large cities. 



The evaporation program inaugurated in 1916 has been continued, 

 with about 50 stations rendering regular reports, which are published 

 in the State section reports. Many requests for additional stations 

 have had to be refused because funds were not available for exten- 

 sions. The data being accumulated are of much value, particularly 

 at this time of increased interest in water resources. A careful digest 

 of accumulated evaporation records is much needed. 



Measurements of rainfall for short periods at places where outdoor 

 events are insured against rainfall are in increasing demand. The 

 conditions set forth in insurance policies require exactness, particu- 

 larly as to time, while the large amounts sometimes named in the 

 policies justify unusual precautions against unauthorized interfer- 

 ence. Three of the weighing-recording gauges described in Circular 



