RECORDS 157 



hysteresis both when the iron is neutral and when it is already, 

 even strongly, magnetized. 



It was found that an increase in the permanent magnetization 

 diminished the permeability and vice versa. The maximum 

 change in permeability thus obtained was 22 per cent. 



The observations of Leonids were made at ]\Ir. Post's obser- 

 vatory. For the purpose of photographing meteor trails four 

 cameras were fastened to the equatorial. Exposures for known 

 times were made on identical parts of the sky. The results 

 showed meteor trails on the plates taken between midnight and 

 sunrise of November 15th. A photograph was obtained of 

 quite a remarkable meteor which appeared at 3:58 A. ]\1. near 

 the radiant point and exhibited a fine head and trail which 

 remained visible for a minute or more. A lantern slide of this 

 meteor was thrown on the screen and attention called to the 

 peculiar details of the head and trail. 



During the night of November 14th and 15th an attempt was 

 made to count the meteors. Miss Edith Post and Miss Gre- 

 nough watched the northeastern and southeastern sky; 418 

 meteors, of which all but a very few were well-defined Leonids 

 were counted. Of these the greatest number was seen between 

 4:30 and 5:30 A. ]\L, on November 15th, when 273 were 

 counted. 



The notes on individual meteors show that many bright Leo- 

 nids fell showing trails which lasted many seconds, and extended 

 10 to 20 degrees. 



Section adjourned, 



F. L. Tufts, 



Secretary. 



SECTION OF BIOLOGY. 

 December 9, 1901. 



Section met at 8:15 P. M., Professor Bashford Dean presiding. 

 The minutes of the last meeting of Section were read and 

 approved. 



