Browning's Pocket Microscope.- Mr. John Browning has recently turned out a pocket microscope, which we have much pleasure In commending to the notice of those of our readers contemplating a sea-side tour. Its general features are shown in the figure. It has two objectives, 1-inch and 2-inch, and a large-field eye-piece. The workmanship, like that of all Mr. Browning's instruments, whether astronomical or general optical, is excellent. This instrument, the most portable yet contrived, is made with the body in two parts, one sliding into the other; the outer portion also slides down through the opening in the stage, which carries the objects. Two legs are hinged at about the center of the instrument; the rod or tube, on which the reflecting mirror is fixed, forms a third leg. Thus, when the two hinged legs are open, the instrument has a firm tripod stand. These legs being opened, the lower part of the body drawn through the stage, and the eye-drawer withdrawn from the body to about the same length is all that is required to set up the instrument ready for use. The tube spoken of as carrying the reflecting minor and forming one of the legs has a fine screw on the inside, and a milled head at the top. This screw gives a fine adjustment. The instrument has eyepiece with a large field, and good objectives. The height, when set up for use, is about 1 foot, and the dimensions of the case which contains the instrument with two objectives, dipping tubes, and pliers complete, is only 6 3/4 inches long, 3 inches wide, and 13/4 inches long.