The "observation-frame," fig. 3, is a mahogany frame, fourteen inches high, eleven inches long, and about four inches wide, having a single groove half an inch deep, and half an inch broad, running within its whole length of eleven inches. The two largest sides have panes of glass fixed in them with small brads. The top, bottom, and one end (this end forming the back) of this frame, are made of solid wood; the back having a small hole, _f_, 2/8 of an inch in diameter in the middle, to allow the spindle before mentioned to pass through it. The end which forms the front of the frame is open, so that any one of the bee-frames can be run into the observation-frame, but may be closed by a piece of tin (_d_) being slipt into the small grooves at _c c_. The observation-frame has two pins, _a, b_, to fit into the 2/8 holes made along the bottom board of the bee-box, shown by the figures, 1, 2, 3, &c., see Plate I, fig. 1, and also two small bolts _r_ and _m_; _r_, the upper one to fix into the holes above X X X, &c., in the mahogany bar; (but this bolt is only used during the operation of drawing out the bee-frames into the observation frame); and the other bolt _m_ at the back of the frame, to fasten into the 2/8 holes, _a, a, a_, &c., made in the lid, I J. When the two pins and the bolts of the observation-frame have been adjusted and fixed, the groove in it will be in a straight line with one of the grooves formed in the bottom board of the box, consequently a bee-frame can be made to slide, by means of the long spindle, in and out of the box, into the observation-frame.