. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. an an inch in diameter, and wound closelyenough to be very easily movable: then on passing the current the coils drawmore closely together,which is very conspicuousupon the screen. If morepowerful action is neededan iron core may be intro-duced, as in the figure, butthis will rarely be neces-sary. Any of the usual ap-paratus for showing therotation of currents, mag-nets, or galvanic cells, iseasily constructed smallf enough for projection, and5 need not be further dweltupon. For many electro
. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. an an inch in diameter, and wound closelyenough to be very easily movable: then on passing the current the coils drawmore closely together,which is very conspicuousupon the screen. If morepowerful action is neededan iron core may be intro-duced, as in the figure, butthis will rarely be neces-sary. Any of the usual ap-paratus for showing therotation of currents, mag-nets, or galvanic cells, iseasily constructed smallf enough for projection, and5 need not be further dweltupon. For many electro-mag-netic experiments it isconvenient to arrange two parallel horizontal brass rods pro-jecting from beneath the front of the condensers, communi-cating with binding screws, as devised by Mr. G. M. small pieces of apparatus, such as here shown, connect-ing with metal spring hooks underneath, have only to be laidon the rods and pushed home to one side, to be in 225 illustrates the simple magnetic effect of a current,the wire being wound irto a small coil at the top of each. FIG. 224.—Rogets Spiral MAGNETISM AND ELECTRICITY 405
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Keywords: ., bookauthorwrightle, bookcentury1900, bookdecade1900, bookyear1906
