390 SCIENTIFIC RECORD FOR 1884. 



418. Prof. William Ferrel has investigated the effect of uprisiuf^ cur- 

 rents upon the atmospheric pressure both in his original memoir of 1857 

 and in his later enlargement of the same published as Meteorological 

 Eesearches by the United States Coast and Geodetic Survey. In the 

 third part of these Researches he gives a hypsometric formula in which 

 the terms depending on the movements of the atmosphere are introduced, 

 but, as he himself shows, these can only be appreciable in most extreme 

 cases. In other respects, however, his formula also represents our latest 

 knowledge on the subject of the attraction of the earth and the effect 

 of atmospheric moisture. (Z. 0. G. M., xix, p. 466.) 



419. [The formula given by Upton in his method of reducing the ba- 

 rometer to sea-level (Ann. Eep. Chief Signal Officer, 1882) introduces 

 some new values of numerical coefficients which, if combined with the 

 improvements made by Ferrel, give us a formula more painfully exact 

 than that of Riihlmanu, but the practical value of these in ordinary hyp- 

 sometry is, of course, limited by the accuracy with which we can ascer- 

 tain the true average temperature of the air.] 



420. Paul Schreiber has published the second edition of his Hand- 

 Book of Barometric Hypsometry. This work has been for some years 

 by far the best general guide to those who wish to derive the best re- 

 sults attainable by the use of the mercurial or aneroid barometer. The 

 author neglects certain retinemeuts relative to the effect of aqueous 

 vapor, but for general use his work is highly to be recommended. Of 

 course, those having a large number of stations at their disposal may 

 prefer to work out s])ecial methods, as has been done by Mr. G. K. Gil- 

 bert for the use of the United States Geological Survey, but it is not 

 yet certain that they will obtain results of much greater accuracy. 



421. E. Hult has discussed the mass of phseuological observations 

 accumulated for the last 10 years in Sweden. One hundred and fifty- 

 seven stations have afforded about 150,000 observations. The previous 

 labors of the French botanist, Adamson, had shown that the develop- 

 ment of the buds is determined by the sum of the daily mean tempera- 

 tures since the beginning of the year. BouSvSiugault had, however, 

 shown that the temperature during the period of rest from growth need 

 not be taken into consideration, and that the length of the growing 

 period is therefore inversely proportional to its mean temj^erature. 

 Linsser concluded that the sums of the temperatures above zero which 

 are necessary to effect development of a plant at any two localities are 

 in direct ratio to the sums of all temperatures at both stations above 

 zero. J. Sachs, the ablest botanical physiologist of the present time, 

 has studied the subject from an entirely different side. He has by di- 

 rect experiment with different plants determined the influence of tem- 

 perature on the development and growth, and found that for each ar- 

 rangement of external conditions about any plant there is a minimum, 

 a best, and a maximum temperature. That is to say, a certain amount 

 of h.eat is necessary, namely, the temperature minimum ; an increase of 



