858 TitAKSACTJO.yS OF THE AMERJCAN L\STlTi'TE. 



increaBcd elongation was observed at any particular temperature, 

 therefore the diminution of cohesion seems to depend not only on 

 temperature and strain, but on the condition of cooling. It wouldbe 

 interesting to the engineer to know whether many repetitions of this 

 process impaired the quality of tlie iron. 



Climate Influenced by Drainage. 

 Prof. Ballot, Director of the Netherlands Meteorological Institute 

 at Utrecht, states that the draining of the Haarlem lake, in Holland, 

 a surface of 19,000 hectares (about 46,951 acres), has had the effect 

 of increasing the average summer temperature of that locality, and 

 the adjacent country, by one-half a degree Centigrade, and of decreas- 

 ing the average winter temperature one-half a degree. 



To Pbesekve Meat in Hot Weather. 

 M. Guignet states in Les Mondes that butcher's meat may be pre- 

 served in hot weather by placing it in large earthern jars, putting 

 cle.an heavy stones upon it, and covering it with skim milk. The 

 milk will become sour, of course, but may afterward serve as food for 

 pigs, and the meat will be found to have kept its natural primative 

 freshness, even after eight or ten days. 



The Cultivation of Truffles. 

 A French journal gives a long account of the cultivation of truffles, 

 and the analysis of twenty-four different kinds of soil in which these 

 cryprogamics grow, which, however, do not show that any particular 

 composition of soil is specially adapted to their cultivation, although 

 it appears that they flourish in those parts of France which are noted 

 for producing good wine. The paper states that truffles were largely 

 cultivated in that country for the use of the ancient Romans in the 

 time of Cicero. Truffles, although the common kinds are indigenous 

 in Pennsylvania and North Carolina, have been but little cultivated 

 in this country. To produce tlie best varieties, even more care is 

 required iu the preparation of the soil than for raising mushrooms, 

 which belong to the same family of plants. 



The Respiration of Aquatic Plants. 

 Experiments made by M. Deheran show that aquatic plants, when 

 kept in darkness, are asphyxiated, and on examining the water in 

 which they died he found no trace of oxygen, but only carbonic acid 



