368 RECORD OF SCIENCE FOR 1887 AND 1888. 



These deep depressions belonged, as we have seen, almost exclusively 

 to the colder period of the year; in order to investigate the tempera- 

 ture of the summer depressions, Loomis has brought together the depres- 

 sions with a central pressure less than 29.4 iuches (746.7 millimeters) 

 for June, July, and August of the three years 1873, '74, '77. For these 

 the average departure of the temperature from its normal value was 

 + G0.5 Fahr., or S^.G C. at the center of the depression and -f 20° Fahr. 

 = lio.l 0. at the above-mentioned warmest point, therefore almost the 

 same as in the winter depressions. 



For the minima of series (&) Loomis has determined only the temper- 

 ature at the center, not its departure from the normal value; the for- 

 mer is -f 4° C. (390.2 Fahr.), which is very high for the season and the 

 latitude of most of these minima. 



Loomis has subjected to a thorough investigation the relation of the 

 wind to the gradient. First, he selected from Hotiioeyer's synoptic 

 charts eighty-one on which there appeared especially well-developed 

 cyclones or anti-cyclones. For meteorologists who desire to submit to 

 a special proof some notable examples, he calls attention to the cyclones 

 of January 12, and December 21-22, 1875; January 22 and March 9 

 and 10, 1870; and the anti-cyclones of December 30-31, 1875, and Jan- 

 uary 1-2 and 13, 187C, Loomis says nothing as to his interpretation of 

 the arrows iudicating the strength of the wind on Hofifmeyer's charts; 

 under the assumption that he has properly considered the half-degree 

 marks on the wind arrows of Hoffmeyer's charts, we can consider the 

 mean strength of the wind deduced by him and given according to the 

 ''1 to 6'' scale as correct Beaufort degrees, siuce the wind estimates of 

 both German and English navigators, on which these charts are based, 

 arealike made on the Beaufort scale; on the other hand, if he has 

 counted the half degree marks as full scale degrees, then all his figures 

 for mean wind force, when they are uneven figures, are too large by 

 one, and therefore his mean values for the whole series will be too large 

 by one-half of a Beaufort degree. 



Loomis's results from Hoffmeyer's charts are summarized in the follow- 

 ing table; the measurements were generally made on that side of the 

 center where the strongest gradients and winds were found. The mean 

 latitude of the centers of the cyclones was 58o.8 north, and that of the 

 anticyclones 49^.7 north. 



