4(J INSECTICIDES, FUNGICIDES, AND "WEED KILLERS. 



flasks on a water-bath heated to 35'-50° C. (9o°-122° F.), pure oxygen or 

 a simple current of air was passed over these mixtures and the experi- 

 ments kept up for eight days. At the exit from the flasks the gas 

 passed through a series of bottles containing substances to retain 

 sulphurous acid in some, hydric sulphide in others. Analyses made of 

 the liquids collected and of the soil mixed with sulphur gave no 

 trace of sulphurous acid, nor of hydrogen sulphide, hyposulphite, or 

 sulphuric acid. Between 25° and 50° C. (77°- 122° F.) therefore sulphur 

 undergoes no chemical modification, and if it acts at this tempera- 

 ture on fungi it is by its own vapours. The odour of a greenhouse or 

 a vineyard is in fact never that of sulphurous acid or hydric sulphide 

 but that of sulphur. There is another reason in favour of the 

 sulphuring of vines. Sulphur would appear in fact to have a direct 

 action on vegetation which it renders more vigorous ; it favours 

 fecundation and otherwise stimulates the maturity of the grape which 

 generally ripens eight days earlier. It is therefore advantageous to 

 sulphur the vine even in the absence of cryptogamic parasites. 



How^ should Sulphur be Applied ? — Sulphur is generally used 

 as a curative agent, and sometimes as a means of prevention. There 

 is no absolute rule for applying sulphur, the essential point is to do it 

 at the right time. The adhesion of sulphur can, in fact, be increased 

 by applying it w^hen the plants are still covered with dew, or after 

 artificial moistening, but that is not indispensable, for dry sulphur 

 generally adheres well enough on the leaves, and chiefly on the 

 diseased parts. The mycelium of the ErysijjhecB retained, in fact,, 

 lumps of sulphur, which persist longer on the spots attacked than on 

 the healthy spots. If a persistent rain comes on or a storm in twenty- 

 four hours after sulphuring, it is well to repeat the operation. Sulphur- 

 ing may be done at any hour of the day. The dose of sulphur should 

 suffice to cover entirely the diseased parts. During great heat it 

 suffices to spread the sulphur on the ground at the foot of the plant. 

 Sulphuring has been used preventively in greenhouses to prevent all 

 cryptogamic diseases from appearing. The sulphur is spread on the 

 soil, or on the heating pipes once a year. The plants thus live in 

 a special atmosphere containing sulphur, which is opposed to the 

 development of fungi, without injuring the plant. Ditt'erent utensils 

 have been used to spread the sulphur. The most simple is the 

 Sablier ordinaire, a vessel of tinned iron, the bottom of which is per- 

 forated. It is filled wnth sulphur and shaken above the diseased plant. 

 This instrument, however, much used in the south, has the drawback 

 of spreading the sulphur very irregularly, and in too large quantity 

 on the diseased plant. The Sablier Jiouppe is constructed on the 

 same style, but it contains meshes of wool which sift the sulphur and 

 distribute it more regularly. But these primitive instruments have 

 been almost everywhere replaced by bellows or blowers. The first was 

 constructed in 1852 by Gonthier, and greatly helped to popularize 

 sulphuring. This is the bellows still used in gardens. It consists of 

 a box to contain the sulphur, which is fitted with a flat pipe at one 

 of its extremities and an ordinary bellows at the other. For large vine- 

 yards there is a more practical instrument, which carries a larger 



