1890.] The Modern Weather Bureau. 23 



decided changes as I could foresee as highly probable ; subsequently 

 the rule was established that every feature must be predicted, and it 

 was under this arrangement that about 85 per cent, of verifications 

 was considered as attained. In May 1871 I compiled for the service 

 a little pamphlet entitled " How to use Weather Maps." This served 

 fto show that the predictions were in no sense empiric ; but were 

 based on deductive processes of reasoning, that utilized the laws that 

 had been established up to that time by such men as Espy, Ferrel and 

 v Wm. Thomson. A. few months' experience gave me an opportunity 

 io show Gen. Myer that the proper study of the storms on the coast 

 required the charting of additional observations from vessels at sea. 

 Accordingly during our first year he issued a circular asking that simul- 

 taneous observations be made on all vessels at 12*43 Greenwich time ; in 

 September 1873 he secured from the Meteorological Congress at 

 Vienna a vote to the effect that simultaneous obbervations throughout the 

 whole Northern Hemisphere were desirable. This vote he construed as 

 an endorsement of the requests independently made by him to every 

 nation of the world asking for the interchange of simultaneous 

 -observations. 



In 1874, such simultaneous observations began to be made by our 

 -American Navy, and now this widespread international request was 

 very generally acceded to, so that in 1875 I had the pleasure of 

 organizing and editing the first issues of the " Bulletins of Simultaneous 

 International Meteorological Observations made at 7.35 a.m. Washington 

 limey To this was subsequently added the corresponding daily chart 

 for the Northern Hemisphere. Such a chart as this constitutes the 

 true and only sufficient basis for the study of the movements of the 

 atmosphere. The only serious defect of the S.S. charts of the 

 Northern Hemisphere resulted from the fact that very few systems of 

 observation except that of the United States pay sufficient attention 

 to the appearances and movements of the clouds, although every one 

 recognises the fact that the clouds have a controlling influence in all 

 our phenomena. Both lower and upper clouds were observed with the 

 greatest pains by myself at Cincinnati and by many of my observers ; 

 such observations began to be telegraphed to Washington and inserted on 

 the manuscript tri-daily Signal Service Charts toward the close of 1871, 

 when a cipher code similar to that used at Cincinnati was adopted 

 by the Signal Office. It must be apparent to any one that the study 

 of the clouds down to the very horizon gives one a comprehensive 

 -knowledge of the atmospheric conditions an hundred miles away. We 

 •often speak of the temperature and the wind as being very local 

 ^phenomena but of the barometric pressure as a more general pheno- 

 menon. What shall we say, then, of the clouds which, as carefully 

 observed by one man, will enable him to say whether the air currents 



