322 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the best varieties of potatoes which enjoy a greater or less 

 immunity from attack. "What it is, in the plant or tuber, 

 that causes this condition is not yet ascertained, and it is 

 thought that possibly, when the cause is known, the more 

 sensitive varieties may be so modified as to have an equal 

 advantage. According to some, the difference consists in 

 the degree of smoothness of the external skin of the potato, 

 while others maintain that it depends upon the thickness of 

 the skin. 19 C, 1871, July 15, 222. 



MANURE FROM DEAD ANIMALS. 



Dead animals are utilized in France by immersing their 

 soft parts in a very feeble solution of hydrochloric acid, 

 which soon transforms them into an odorless pulp. This is 

 to be mixed with phosphate of lime, and the result is a ma- 

 nure of the best quality. 9 C 9 February \ 1870, 14. 



UTILIZING FISH OFFAL. 



An ingenious method proposed for utilizing the residue 

 and'offal of fish consists in first boiling it together with one 

 tenth of its weight of cheap oil, heating it up from 250 to 

 300 Fahrenheit. It is then treated with sulphide of carbon, 

 whereby the oil naturally contained in the fish, as well as 

 that which was added, is extracted, and a mass is left, quite 

 dry, and containing from five to six per cent, of nitrogen, and 

 from twelve to fifteen per cent, of phosphate of lime. 1 A, 

 April 29, mo, 202; 



ACTION OF FOTASII ON FRUIT-TREES. 



Dr. George B. Wood, in a communication to the American 

 Philosophical Society in Philadelphia, presented the result of 

 certain experiments made by him upon the effect of salts of 

 potassa when applied to grain and fruit-producing soils. In 

 his view, the depreciation of the productiveness of apple, 

 peach, and quince orchards is due to the exhaustion of potash 

 from the soil. Several of such orchards, formerly very valu- 

 able, but which had within a few years ceased to bear much 

 fruit, on being treated with an application of wood ashes to 

 the roots of the tree, became completely revived, producing 

 full crops the following year. A still more striking effect 

 was seen the second year, under a renewal of the application. 



