i66 THE POPULAR SCIENCE MONTHLY. 



tage over a liquid, as it will more effectually permeate the soil and 

 reach the lice. The following is the method of procedure in their own 

 words : 



" Make three holes around the vine, the depth to vary according to nature 

 of soil, but generally about 1\ feet (80 centimetres). Hitherto we have made 

 these holes with a pointed iron bar, driven by a maul. When the hole is made 

 the bar is withdrawn, and a tube, furnished with a funnel at one end, is inserted 

 in its place. About two ounces of sulphuret of carbon are then poured into the 

 tube, which is immediately corked. . . . The vapor of this sulphuret of carbon 

 permeates the soil, and impregnates all the roots of the vine. The gas engen- 

 dered is not, like the liquid itself, fatal to the vine, but invigorates it. Its effects 

 are, however, sure death to the insect, and, if a vine is examined eight days 

 after the treatment, the lice are found dead and carbonized. At the end of fif- 

 teen days nothing but the effects of the lice is seen. Long and corroborative 

 experience has demonstrated that about four ounces (100 grammes) of the liquid 

 is sufficient for an ordinary vine ; but sprinkling on the surface must be care- 

 fully avoided, as it is then very injurious to the vine ; whereas as much as a 

 pound may be made to penetrate the soil without injury to the roots." 



Soon after the announcement of this method, I employed it as a 

 test on three vines, which I knew to be infested with Phylloxera, using 

 three ounces to the first, six ounces to the second, and nine ounces to 

 the third, the soil being a light clayey loam. At the end of twelve 

 days I found plenty of living lice on the first and second vines, and 

 such were found long afterward, though in small numbers, uj) to the 

 time of the freezing of the ground. On the third vine all the lice 

 were evidently charred, but the vine was also plainly injured, as the 

 leaves wilted as though they had been scorched, though, whether from 

 the vapor issuing from the ground, or from the injury to the root, it 

 was impossible to determine — I think, however, from the former, as 

 the larger roots were yet alive late in the season, and the vine seems, 

 at this writing, to be living. 



After very careful and laborious experiments made in France at 

 different points, and on different kinds of soil, by a commission specially 

 charged with studying the action of this chemical, under the method 

 proposed by Messrs. Monestier, Lautand, and D'Ortoman, it fails to 

 fulfill the sanguine expectations of these gentlemen. The liquid is 

 costly, its application is laborious, and there is great difficulty in 

 reaching and killing all the lice without injuring the vine. Great cau- 

 tion must also be had in its use, as it is extremely volatile and explo- 

 sive, the vapor igniting at a great distance from the vessel contain- 

 ing it. 



While, therefore, not very satisfactory results have followed the 

 use of pure insecticides, the application of fertilizers, intended to in- 

 vigorate the vine, and at the same time injure the lice, has been more 

 productive of good. Especially has this been the case with fertilizers 

 rich in potassic salts and nitrogenous compounds, such as urine. 



Sulphuret of potassium, dissolved in liquid manure; alkalino-sul- 



