CAUSE AND CURE OF MILDEW. 301 



first appearance, there will occur two or three days in which 

 the hygrometer indicates an excessive dryness of the atmos- 

 phere. If a day of this intense dryness comes on, you will 

 have a flash of mildew come over your vines all at once. It 

 will come within a few hours. The next day perhaps there 

 will come a rain, and the mildew on that day will not make 

 any progress, but the flash of mildew that came the day 

 before all stays there. The next day perhaps it will rain, 

 and there is no danger. You go out that day and you for 

 the first time see some mildew, and you will say that it is the 

 wet weather that makes those vines mildew. You are a very 

 careless observer. You have not watched it all the time. 

 Even the slightest outward appearance of moisture in the 

 atmosphere appears to stop its growth all at once. It ceases 

 to grow for two or three days, and then there comes another 

 day of intense dryness, and that mildew increases enormously. 

 This last season was a fine negative illustration of this theory. 

 The month of June was not only dry as far as the rain-fall 

 was concerned, but it was excessively dry hygrometrically. 

 The streams were all very small, and if there came a rain, 

 the moisture would be dried up by the next day. The winds 

 came from the north-west, and sucked up the moisture like a 

 sponge. In July, there came a rainy season, there was a 

 great deal of humidity in the atmosphere, and the result was, 

 I did not see a spot of mildew during the whole season. 

 That, of course, is negative proof only, but on the other 

 hand, a hygrometrically wet June followed by a dry July has 

 always given us a large amount of mildew. 



Now, in regard to the application of remedies, you are 

 liable to be deceived. A man finds a little mildew on his 

 vines. Perhaps he saw it day before yesterday, and it has 

 not increased a bit since. He applies sulphur when it is 

 first seen, and the next day he does not find any increase, and 

 he says that sulphur is a specific against mildew. But he 

 should observe what happened without the application, before 

 he said that was a remedy. I have tried the application of 

 sulphur under glass a great deal, and I have never succeeded 

 in producing any great eflect with dry sulphur under such 

 circumstances, but half an ounce of sulphur volatilized on a 

 warm surface will unfailingly kill mildcAV. I trust that the 



