Proceedings of the Folytechnjc Association. 861 



way, causes electricitj to tend to an equal distribution, might be 

 called, if we we were permitted to coin a term in familiar language, 

 attraction of equilibrium. The attainment of a quiescent state, how- 

 ever, does not imply any cessation of this force, but merely uni- 

 form diffusion ; and, therefore, perfectly equal attraction in all 

 directions." 



Ink from Elder Berries. 



The Deutsche Industrie Zeitung publishes the following process : 

 The bruised berries, after being kept in an earthern vessel for three 

 days, are pressed and filtered. The juice is of an intense dark color, 

 requiring about 200 parts of water to reduce it to the shade of dark red 

 wine. To twelve and one-half quarts of this filtered juice add one 

 ounce of sulphate of iron and one ounce of crude pyroligneous acid. 

 The ink thus prepared has, when first used, a violet color, but, when 

 dry, is an indigo blue black. This ink is superior, in some respects, 

 to that prepared from galls ; it does not become thick so soon ; in 

 writing it flows easily from the pen, without gumming, and the let- 

 ters formed by it do not spread on the paper and run into one 

 another. 



Keeping Fruit. 



After giving a condensed account of experiments in })reserving the 

 fruit of 1S67, according to Prof. Nyce's system, which has already 

 been fully explained in The Tribune, Tilton's Journal of Horticul- 

 ture says : We think our readers will be struck with one remarkable 

 difference between the fruit kept in this house and that preserved 

 beyond its season in a common ice house, viz., that the former was 

 longer in ripening, and kept longer when ripe, than that which had 

 never been in the house, while fruit preserved in the ordinary ice 

 house is well known to perish as soon as removed. Perhaps, how- 

 ever, this difterence would not be so great in fruit taken from the 

 house in warm weather, for it will be noted that nearly all that men- 

 tioned was removed from the house in the winter. The accounts of 

 last year's crops are not so favorable ; but this is said to be largely 

 owing to the want of care on the part of those in charge of the house 

 in maintaining a uniform temperature and degree of moisture. Con- 

 stant care and vigilance in regard to these points is absolutely neces- 

 sary, quite as much so as in managing a green house. The princi- 

 ples upon which the flavor and fragrance of fruit depend are 

 extremely volatile ; and, with all the attention that could be given, 



