side pieces is fastened another board, on which is marked the hour circle, F. Through this board passes the lower end of the polar axis, having a shoulder turned up on it at K, and is secured by a wooden collar and pin underneath.  On to the upper part of the polar axis is fastened the declination circle, C, 51/2 in. diameter, made of 1/4 in. baywood, having the outer rim of a thin compass card divided into degrees pasted on to it.  The hour circle, F, is half of a similar card, with the hours painted underneath, and divided to 20 minutes.  G is the hour index.  D is a straight wooden pointer, 12 in. long, having a piece of brass tube, E, attached, and a small opening at J, into which is fixed the point of a common pin by which to set the pointer in declination.  H is a nut to clamp pointer in position.  By this simple toy affair I have often picked up the planet Venus at midday when visible to the naked eye.—­T.R.  Clapham in English Mechanic.

[Illustration:  A STAR FINDER.]

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The best mode of finding or tracing trichinae in pork by means of a microscope is the following:  Cut a very thin longitudinal slice of the muscle by means of a very sharp knife or razor.  Press it between two glass slips, and examine by transmitted light, The coiled trichinae may be readily distinguished from the muscle fiber.

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