8G2 7'ii Ays ACTIONS OF THE Ameiucax Ixstitute. 



fruit growers had previously failed to do anytliino; more than to keep 

 the winter pears a month be^yond the usual time of ripening in an ordi- 

 nary cellar ; hut summer and autumn years, such as Bartlett, Seckel or 

 Louise Bonne, of Jei-sey, have never before been kept in perfect order 

 until January or February. But those who expect to keep fi'uit per- 

 fectly, without the utmost care in gathering and handling, and the 

 most scrupulous attention to neatness and cleanliness, as well as to 

 the general management of the house, will certainly be disappointed. 

 We may add that specimens of fruit taken from the house at Cam- 

 bridge April 10th, 1867, were carried to England by Mr. "Wilder, 

 and presented to Mr. Kivers, by whom they were tested at a dinner 

 party on the 23d of the same month, exciting much gratification and 

 surprise at their perfect preservation ; some of Mr. Rivers' guests 

 being at first rather incredulous of his statement that beside having 

 been kept over from the previous season, they had made a voyage 

 across the Atlantic. 



Cracking of Collodion Films. 



At a late meeting of the London Photographic Society, the Chair- 

 man, Mr. J. Glaisher, F. R. S., remarked that he had often regretted 

 that ladies so seldom attended the meetings of the Society. He was 

 glad to see two present at that meeting, and one of them, Mrs. Cam- 

 eron, desired to say a few words to the members. 



Mrs. Cameron said she wished to obtain the opinion of members 

 as to to the cause of cracking in the film of her negatives. She pro- 

 duced a large negative of Sir John Herschel in April, 1867, which 

 was now, together with many others taken by her, covered with 

 honey -comb, like cracks. The collodion film appeared to be cracked 

 under the varnish, the latter being intact. During the last six years 

 she had taken about 600 negatives, and, during the last two years 

 about forty-five of these had cracked, the injury taking place at all 

 seasons of the year. A long conversation and examination of some 

 of the negatives alluded to followed, in the course of wliich it was 

 pointed out that the cracks were through the varnish as well as collo. 

 dion, and that they often resulted from the use of So^hnee varnish. 



Mr. Thomas said cracks in the collodion film had, unfortunately, 

 been occasionally seen ever since the introduction of the collodion 

 process, no matter what collodion or what varnish had been used, 

 without the fault being due to either, but rather to the incompatibility of 

 the same two samples when in conjunction. Changes in temperat re 



