832 EXPERIMENT STATION RECORD. 



observations in cooperation with the International Cloud Commission at 

 15 different places in the United States during the period from May 1, 

 1896, to July 1, 18l>7: 



"In order to submit these results to a careful discussion, it has Ijeen necessary to 

 prosecute a critical comparative study of several important theories heretofore pro- 

 posed by meteorologists, so that the comparison between observations and theoret- 

 ical computations can be guital)ly carried out. Accordingly, a standard mathematical 

 system has been constructed, including in a definite notation the constants, the ther- 

 modynamic, and the hydrodynamic formulfe pertaining to the atmospheric physical 

 processes and motions, by means of which the work of the several authorities can be 

 reduced to one set of typical equations. The theories of the American and the Ger- 

 man schools of meteorology have been contrasted, and the results derived from them 

 have been compared with the facts obtained from these cloud observations. The 

 grouping of the data secured by the theodolites and the nephoscopes has been so 

 carried out as to make such a comparison simple and direct, the outcome being inter- 

 preted to mean that a modified theory of atmospheric motions is required to explain 

 the local anticyclonic and cyclonic circulations, while the theory of the general 

 cyclone, though partially sustained, also needs improvement in several important 

 details. Furthermore, the thermodynamic processes have been submitted to a rigor- 

 ous computation, especially in connection with cumulus clouds, by means of which 

 the limits of the four standard stages, and the mean gradients of pressure, tempera- 

 ture, and vapor tension within each stage, have been carefully determined. The 

 construction of this system of computation has put us in possession of a method of 

 discussing several important fundamental characteristic features of the atmosphere, 

 and it is evident that a continuation of research along these lines will not only tend 

 to make of meteorology an exact science, but will also enable us to practically con- 

 struct quite accurate daily weather maps at moderate elevations, that is, up to 1 and 

 2 miles above the surface. Sucli an outcome would amply repay the expenditure of 

 much time and labor in the preliminary steps required to reach this goal; yet it is 

 thought that the results contained in this report are such as to warrant the entering 

 upon their actual application at once, with the expectation that further experience 

 will merely improve upon the close approximations already secured." 



The author believes that increased equipment for observations of 

 this character, including- a permanent station for theodolite observa- 

 tions at Washington, D. C, and the equipment of each of the tirst- 

 order stations of the Weather Bureau with a nephoscope will furnish 

 the basis for a more accurate s^'stem of weather forecasting. To this 

 end he recommends especiallj^ that the data collected be used in the 

 construction of auxiliar}' maps showing the atmospheric motions at 

 elevations of 3,5()0 and 1U,00(> ft. 



Amount of chlorin in rain water collected at Cirencester, E. 

 KiNCH {.Tour. Chcm. Sue. [Lo7idon\ 77 {1900), No. W, 2>P- ^^'^1- 

 127-3). — The total rainfall, and its content of chlorin, is gWen for each 

 six months (October to March and April to September) from October 

 1, 1886, to September 30, 1900, together with averages for the winter 

 and summer periods and for 14 and 26 years. The averages are as 

 follows: 



