. Journal of applied microscopy and laboratory methods. ration of an attempt to take a flashlight of agroup around the camp fire at night. The magnesium was placed in a tin panwith a paper between the powder and the pan, the paper trailing outside so as togive a chance for lighting. The pan was placed on a bench with a tent as back-ground. Nearly an ounceof magnesium was foundnecessary to produce a satis-factory picture. The camerawas placed, and the personin the middle of the groupwas given a candle, whichwas used to determine whena sharp focus was giving the candle to theparty at
. Journal of applied microscopy and laboratory methods. ration of an attempt to take a flashlight of agroup around the camp fire at night. The magnesium was placed in a tin panwith a paper between the powder and the pan, the paper trailing outside so as togive a chance for lighting. The pan was placed on a bench with a tent as back-ground. Nearly an ounceof magnesium was foundnecessary to produce a satis-factory picture. The camerawas placed, and the personin the middle of the groupwas given a candle, whichwas used to determine whena sharp focus was giving the candle to theparty at one end, then trans-ferring it to the other end, asuitable arrangement washad. The shutter was FIG. 12. AN EXPERIMENT IN REARING DRAGON FLIES. ^ u 4- iU opened about the time thetrail of paper was lighted, after which the operator walked around and took aplace in the group. After the flash he returned to the camera, closed the shutter,and later made development. On this occasion there was enough smoke tomake part of the picture a trifle 127! Journal of Applied Microscopy Figure 12 is a device suggested by Calvert for rearing dragon-flies, suitableenvironment having been obtained. The cylinders of wire netting are placed inthe water, and the insects placed therein. When they transform it is possible toidentify the adults, and consequently distinguish between young. The picturegiven is from an experiment performed at the laboratory. Figure 13 illustrates tophotographers the possi-bilities of taking bird nestsin-doors. The nest is thatof Wrights flycatcher,E mp ido n a x iv r ig h t i /,Baird. A position wastaken in front of the win-dow, though out of thedirect sun. A black feltcloth was used as a back-ground, the nest being seton the cloth in the anglemade by the table and apile of books. A mirrorwas adjusted so as tothrow light into the nest,as the side next the win-dow was naturally darkerthan the other. The nestwas several inches long, but was incUned so as to
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
