380 ANNUAL EECORD OF SCIENCE AND INDUSTRY. 



and tear, does not exceed seven or eight shillings per ton. 

 2^, XX., 64. 



THE NEW PHYLLOXERA EEMEDT. 



La Nature^ in a late review of the researches of M. Dumas 

 relative to the practical efficiency of the alkaline sulpho- 

 carbonates as destroyers of the phylloxera, affords us the fol- 

 lowing information upon the philosophy of the operation of 

 this class of salts: The sulpho-carbonates of the alkalies are 

 produced by calcining their respective sulphates with carbon, 

 by which the mono-sulphide is produced, and agitating a 

 concentrated aqueous solution of this with carbon disulphide. 

 The sulpho-carbonates obtained as liere described are free 

 from disagreeable odor, are not dangerous to handle, are 

 non-inflammable, and comparatively stable. In the presence 

 of acids, however, even of the weakest, and notably when 

 acted upon by the carbonic acid of which a moist, arable soil 

 invariably contains a certain quantity, the sulpho-carbonates 

 are decomposed into carbonates, with the liberation of car- 

 bon disulphide and sulphuretted hydrogen, both of which, 

 and especially the first, are known to be highly efficient in- 

 secticides. It has been found that it is not only necessary 

 to destroy the insects upon the vines and roots, but likewise 

 to poison the earth in the vicinity of the same, and render it 

 uninhabitable by them. For this purpose the sulpho-car- 

 bonates seem to be admirably adapted, inasmuch as, by their 

 tardy decomposition, they furnish a slow but constant supply 

 of the poisonous gases for some days. Experiments have 

 shown that 1442 grains of the sulpho-carbonate of potassa 

 will exterminate the insects from 198 to 284 cubic feet of 

 earth, killing not only the phylloxera, but likewise the 

 larvae of larger insects. To apply the remedy, it is recom- 

 mended to remove the earth from the foot of the vine 

 about a foot deep and sixteen inches broad, into which is to 

 be poured five or six quarts of water mixed with six or eight 

 quarts of the sulpho-carbonate solution at 40 Baume. When 

 the liquid is well absorbed the hole is closed, and the same 

 process gone through on another vine. By following this 

 method the penetration of the solution to the deepest roots 

 is insured. Another method of application proposed by M. 

 Dumas is to mix the sulpho-carbonate with twice its weight 



