Either a well-made, powerful, vehicular lamp with its bull's-
eye (if any) removed could be used for this purpose, or a portable
generator of any kind might be connected with the burner through a
flexible tube. It is necessary that the lights should be lit just before
dusk when the weather is fine and the nights dark, and for some twenty
evenings in June or July, exactly at the period of the year when the
perfect insects are coming into existence. In some of the vineyards of
Beaujolais, in France, where great havoc has been wrought by the pyralid,
a set of 10-candle-power lamps were put up during July 1901, at distances
of 150 yards apart, using generators containing 6 oz. of carbide, and
dishes filled with water and petroleum 18 or 20 inches in diameter. In
eighteen nights, some twenty lamps being employed, the total catch of
insects was 170,000, or an average of 3200 per lamp per night. At French
prices, the cost is reported to have been 8 centimes per night, or 32
centimes per hectare (2.5 acres). In Germany, where school children are
occasionally paid for destroying noxious moths, two acetylene lamps
burning for twelve evenings succeeded in catching twice as many insects
as the whole juvenile population of a village during August 1902.
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