METEOROLOGY. 211 



tory and construction of the thermometer and explains its use in candy making 

 and cooliiug, in the dairy, in the incubator, and in orchards, as well as occa- 

 sional uses, such as in the detection of fever in farm animals. 



The variation with meteorolog'ical conditions of the amount of radium 

 emanation in the atmosphere, in the soil g'as, and in the air exhaled from 

 the surface of the ground at Manila, J. R. Weight and O. F. Smith {Phys. 

 Rev., 2. ser., 5 {1915), No. 6, pp. 459-482, fig. 1). — In continuation of observa- 

 tions previously reported (E. S. R., 31, p. 511), an attempt was made to deter- 

 mine definitely to what extent the amount of radium emanation in the air is 

 dependent on weather conditions. The methods used were substantially the 

 same as those employed in the previous observations. 



As a result of observations extending over about 13 months, the variation 

 of the radium-emanation content of the atmosphere was found to follow quite 

 closely the variations in rainfall and wind movement. " The ratio of the maxi- 

 mum to the minimum for the year was found to be appproximately as 10:1. 

 The mean of the monthly means gives for the radium equivalent of the emana- 

 tion per cubic meter of air a value of 71X10'" gm. The month of January 

 shows the highest monthly mean for the radium-emanation content, the mini- 

 mum value for the rainfall, and a low value for the total wind movement. 

 The month of July gives the lowest monthly mean for the emanation content, the 

 maximum value for the rainfall, and the highest total wind movement. Every 

 other month of the year shows a very similar relation. No direct connection 

 has been discovered between the emanation content and atmospheric pressure 

 or humidity. The effect of the direction of the wind seems at best very 

 indefinite." 



The emanation content was considerably greater during the night than during 

 the day. " Observations for the interval from 11 p. m. to 5 a. m. gave a inean 

 value 3.31 times greater than the mean value for the interval from 11 a. m. to 

 5 p. m. This variation has been found to be closely related to the variation in 

 the total wind movement during the period, a high value of the wind move- 

 ment corresponding to a low value of the emanation content. 



" The rate at which radium emanation is exhaled from the surface of the 

 ground shows a decided decrease after periods of heavy rain. This decrease 

 has been found in some cases to be almost 60 per cent of the rate of exhalation 

 for fair weather." 



The radium-emanation content of soil gas was determined at depths of 30, 

 70, and 120 cm., respectively. The variation in the radioactivity of the gas 

 collected at a depth of 30 cm. was found to follow closely the variation in the 

 emanation exlialed from the surface of the soil, a decrease in the exhalation 

 resulting in a corresponding increase in the emanation content of the soil gas. 

 Soil gas collected at depths of 70 and 120 cm. showed only slight variations with 

 the weather conditions. " The average value of the emanation content for the 

 gas collected from the 120-cm. pipe was found to be a 304.5X10"" gm. per' liter, 

 or over 4,000 times the mean value for atmospheric air. The mean value for 

 the 30-cm. pipe was only about one-seventh that for the 120-cm. pipe." 



[Meteorological observations], R. O'Connor et al. {Ann. Rpt. Dept. Agr. 

 Trinidad and Tobago, 1913-14, pp. 34, 61-61). — ^Tables show the rainfall during 

 the year ended March 31, 1914, at River Estate, from 1S62 to 1913, inclusive, 

 at the Royal Botanic Gardens, and for the calendar year 1913 at other places 

 in Trinidad and Tobago, as well as various meteorological observations during 

 1913 and preceding years at the St. Clair Experiment Station, Trinidad. 



Weather conditions (Union So. Africa Dept. Agr. Bpt. 1913-14, PP- 287- 

 291).— The general weather conditions in the Union of South Africa during the 



