432 PROCEEDINGS OF THE AMERICAN ACADEMY. 



sets from individual storms were made, including date, temperature, 

 snow fall, condition of the clouds, direction and force of the wind, and 

 sometimes notes as to the general character of the snow crystals and 

 their changes as the storm progressed. 



The magnifications used range from 52 to 31 diameters, and are 

 evidently much higher than those of previous collections. The same 

 general types of crystals noticed by previous observers recur here, such 

 as the star form, star form with solid nucleus, and tabular form, while 

 the columnar form (hexagonal prism and base) is rare, and the hexago- 

 nal pyramid is not seen. Variations of skeleton growth of hexagonal 

 plates, comprising the base and prism of the first order, predominate ; 

 less commonly the intermediate axes are visible by lines of growth 

 or air inclusions, and rarely a triangular development suggests rhombo- 

 hedral symmetry. The presence of tl\e varied markings due to inclu- 

 sions of air is much more prominent in these than any as yet published, 

 owing to the higher magnification and the superb technique of the 

 photographs. Mr. Bentley also confirms the previous observation, that 

 large stellate crystals are more common at the higher temperatures and 

 the tabular ones at the lower. 



Some photographs of frost crystallizations are included. 



Reserving for a future communication the result of more detailed 

 study, a preliminary account is here given of this large and perfect 

 collection which may justly be called a monument to the patience, skill, 

 and enthusiasm of the maker.* 



* In " A Study of Snow Crystals," recently published in Appleton's Popular 

 Science Monthly, (May, 1898, pp. 75-82,) by W. A. Bentley and G. H. Perkins, the 

 authors give some account of this collection, with a reproduction of 27 examples. 



