AMERICAN INSTITUTE. 289 



showing their growth from year to year. Salmon, from the river 

 Danube, trout, from the lakes of Switzerland, and graylings, from 

 Lake Constance. These last were hatched this spring. The sal- 

 mon and trout, are (at fourteen months old,) from 4| inches to 

 16| inches in length. There are two salmon, three years old, 

 one of which is nearly 19 inches long by 13 inches in circumfer- 

 ence. A young salmon of four inches long, and weighing about 

 four ounces, when permitted to go to the ocean, returns to the 

 rivers in about six weeks, weighing from five to six pounds weight. 

 Naturally, a salmon grows in three years to about 25 pounds 

 weight. Artificially, he only gains at the Thuringen establish- 

 ment, about five pounds weight. 



[Journal de la Societe Imperiale et Ccntrale D'Horticulture. Paris, June, 1857.] 



Extracts translated by H. Meigs. 



NEW APPLICATION OF ELECTRO MAGNETISM TO HOR- 

 TICULTURE. 



Mons. Becquerel, of the Institute, reports, that being charged 



by the Society of Horticulture with the examination of what has 



been done relative to an electro-magnetic apparatus, contrived to 



regiftate the temperature in cocooneries, and hot houses, &c., in 



order to have a steady uniform state of it, independent of windows 



and doors, by means of a breathing hole, (soupirail,) to open and 



shut by means of an ingenious electro-magnetic apparatus, which 



operates as the interior temperature rises or falls. 



I think that the extent of the force, as applied, is not sufficient 

 even for hot houses or cocooneries of common dimensions. The 

 project of Mons. Carbonnier, is a rational one. I ought to remark 

 here, that electricity may be usefully employed; not as a force, 

 but as the means of transmitting force. 



Report upon the elementary treatise of Mushrooms, eatable or 

 poisonous, by Mons. Dupuis, professor of forest culture, in the 

 school of Grignon — by Dr. Boisduval. 



You have charged me to give an account of this work, and I 

 comply. The title indicates it to be, not a general work on the 

 innumerable family of mushroooms, but a special treatise, show- 

 ing the difference between the eatable and the poisonous kinds. 

 [Am. Inst.] 19 



