Febeuaey 23, 1906.] 



SCIENCE. 



315 



eulation regarding the amount of water needed 

 to moisten the air indoors to a reasonable de- 

 gree (Mo. Weather Rev., XXXIIL, 208). He 

 finds that in southeastern Nebraska, in a 

 house containing 14,000 cubic feet, from 

 twenty to forty quarts of water should be 

 evaporated daily. This amount of evapora- 

 tion does not increase the relative humidity 

 by more than ten per cent. Experience has 

 shown that, under the conditions of Mr. 

 Loveland's experiments, the humidity indoors 

 should not exceed forty per cent., otherwise 

 condensation on windows will be trouble- 

 some. Double windows doubtless allow a 

 greater increase in humidity without the 

 disagreeable result here referred to. The 

 ten per cent, increase makes a decided 

 difference in the feeling of tiie air. The tem- 

 perature of the room was kept about as high 

 with the added moisture as if the air had been 

 drier. (In some experiments made a few 

 years ago by Dr. Henry J. Barnes, of Boston, 

 the moisture added to the air by means of a 

 ' humidifier ' made the room comfortable at a 

 temperature several degrees lower.) 



ROYAL METEOROLOGICAL SOCIETY. 



Recent meetings of the Royal Meteorolog- 

 ical Society, as reported in the Quarterly 

 Journal of the society, brought out several 

 papers of general interest. An address on 

 ' The Growth of Instrumental Meteorology,' 

 by Richard Bentley, laid emphasis on the 

 seven great weapons of the meteorologist, the 

 thermometer, hygrometer, rain gauge, barom- 

 eter, anemometer, kite and heliograph, and 

 directed attention to our indebtedness to Italy 

 in this science, as in others. W. H. Dines, in 

 ' An Account of the Observations at Crinan 

 in 1904, and Description of a new Meteoro- 

 graph for use with Kites,' reported upon the 

 kite work carried on under the direction of a 

 joint committee of the Royal Meteorological 

 Society and of the British Association. Dur- 

 ing the summer of 1904 a naval vessel was 

 placed at the disposal of this committee by the 

 Admiralty. Richard Straehan, in a paper on 

 ' Measurement of Evaporation,' thought it de- 

 sirable to estimate, even empirically, the prob- 

 able amounts of evaporation and percolation. 



' Normal Electrical Phenomena of the Atmos- 

 phere ' were discussed by George C. Simpson, 

 who stated the chief lines along which investi- 

 gations have been made during the last few 

 years, the conclusions arrived at, and the chief 

 problems awaiting solution. A paper by S. P. 

 Fergusson, of Blue Hill Observatory, described 

 the automatic pole star recorder, and the om- 

 broscope in use at Blue Hill. The latter in- 

 strument records with great exactness the 

 time of commencement and the duration of 



ANNUAL RINGS OF TREE GROWTH. 



In the Monthly Weather Review, Vol. 

 XXXIII., 1905, 250-251, Professor E. E. 

 Bogue, of the Agricultural College at Lan- 

 sing, Mich., gives the results of an investiga- 

 tion made by him of the seasonal and annual 

 rapidity of growth of trees in Stillwater, Okla., 

 between October, 1898, and September, 1901. 

 Twenty-seven trees were studied, nearly all of 

 them being yearlings or two-year-olds. The 

 results show that there was a close relation 

 between rainfall and tree growth. At Lan- 

 sing, Mich., an investigation was made into 

 the average width of the annual rings of 

 growth of forty-two trees, during the period 

 1892 to 1904, in relation to the annual pre- 

 cipitation. The data show that a precipita- 

 tion of 30 to 35 inches gives a width of ring 

 of from 0.11 to 0.15 inch, and that abnormally 

 large or small precipitation is evidenced by 

 the tree growth of the following year. 



CLOUD STUDIES IN THE PYRENEES. 



The results of detailed cloud studies carried 

 on at the Pic du Midi Observatory and at the 

 base station, Bagneres, have been discussed by 

 Marchand (Met. Zeitschr., Nov., 1905). Of 

 general interest may be noted the following 

 conclusions. Three different elements occur 

 in clouds: (1) Water drops; (2) small, more 

 or less crystalline ice particles, without definite 

 forms; (3) small, regular, transparent hexag- 

 onal crystals (plates, stars, needles, etc.). 

 Cirrus and cirro-stratus are composed of the 

 third of these elements. Cirro-cumulus clouds 

 also contain these crystals, but probably are 

 chiefly made up of ice particles of distinct 



