SiO . PHILOSOPHICAL TRANSACTIONS. TaNNO 1772. 



from being eaten or damaged by caterpillars. 2d. In preventing blights, and 

 their effects on fruit and other trees. 3d. In the preservation of crops of wheat 

 from the yellows, and other destructive insects. 4th. Also in saving crops of 

 turnips from the fly, &c. &c. 



1 St. Mr. G. was led to his first experiments, by considering how disagreeable and 

 offensive to our olfactory nerves the effluvia emitted by a brush of green elder 

 leaves are, and thence, reasoning how much more so they must be to those of a 

 butterfly, which may be considered as being as mucli superior to us in delicacy 

 as inferior in size. Accordingly he took some twigs of young elder, and with 

 them whipped the cabbage plants well, but so gently as not to hurt them, just 

 as the butterflies first appeared; from which time, for these two summers, 

 though the butterflies would hover and flutter round them like gnomes or sylphs, 

 yet he could never see one pitch, nor was there apparently a single caterpillar 

 blown, after the plants were so whipped, though an adjoining bed was infested 

 as usual. 



2d. Reflecting on the effects abovementioned, and considering blights as 

 chiefly and generally occasioned by small flies, and minute insects, whose organs 

 are proportionably finer than the former, he whipped the limbs of a wall plum 

 tree, as high as he could reacli ; the leaves of which were preserved green, flourish- 

 ing, and unhurt, while those not 6 inches higher, and thence upwards, were 

 blighted, shrivelled up, and full of worms. Some of these last he afterwards 

 restored by whipping with, and tying up, elder among them. It must be noted 

 that this tree was in full blossom at the time of whipping, which was much too 

 late, as it should have been done once or twice before the blossom appeared. 

 But he concluded from the whole, that if an infusion of elder was made in a tub 

 of water, so that the water might be strongly impregnated with it, and then 

 sprinkled over the tree, by a hand engine, once every week or fortnight, it 

 would effectually answer every purpose that could be wished, without any risk of 

 hurting the blossoms or fruit. 



3d. What the farmers call the yellows in wheat, and which they consider as a 

 kind of mildew, is in fact occasioned by a small yellow fly with blue wings, about 

 the size of a gnat. This blows in the ear of the corn, and produces a worm, 

 almost invisible to the naked eye; but being seen through a pocket microscope, 

 it appears a large yellow maggot of the colour and gloss of amber, and is so 

 prolific that Mr. G. distinctly counted 41 living yellow maggots or insects, in the 

 husk of one single grain of wheat, a number sufficient to eat up and destroy the 

 corn in a whole ear. He intended to have tried the following experiment sooner ; 

 but the dry hot weather bringing on the corn faster than was expected, it was got 

 and getting into fine blossoms ere he had an opportunity of ordering as he did; 

 but however the next morning at daybreak, two. servants took two bushes of 

 elder, and went one on each side of the ridge from end to end, and so back again, 



