=Observation Hive.=--This consists of a glass case made to hold one standard frame, a shallow frame, and a row of sections. The bees can thus be seen at work on the combs. It is mounted on a pivot, through which the bees must pass to the entrance. Of course, the "observation hive" is not intended to keep bees in for more than a few days at a time, and when it is in use care should be taken not to expose the combs or the bees to the heat of the sun. CHAPTER III =Bee-keepers' Requisites= =Comb Foundation.=--It is this wonderful invention that with the bar-frame has made bee-keeping a practical factor; without it, indeed, the bar-frame hive would be useless from a commercial point of view. The "comb-foundation" is a thin sheet of bees-wax, impressed by machinery, on both sides, with true hexagonal, or six-sided, bases of cells, a slight foundation for the walls being also impressed. Thus the bees are given a start, as it were, in their work. This foundation is made either with "worker" or "drone" cells and the bees will follow unfailingly the lead thus given them in their building. It is made in three degrees of thickness--"thin," "medium," and "thick"; the first for use in sections, and the others in the brood chamber. As a rule bee-keepers in England buy only the worker-brood foundation, for should drones be required they can be secured by merely cutting away the lower part of a honey-comb, or supplying only half a sheet of foundation in the frames, for the bees will almost without fail build drone cells on these. Foundation is catalogued by all makers of bee-keeping appliances, but it should be obtained only from reliable sources, for one of its essentials is that it should be made from pure bees-wax thoroughly cleansed and sterilized. Otherwise it may contain germs of brood disease. _Old Foundation._--If a stock of foundation should at any time be left in hand it is advisable that it should be slightly warmed before it is given for the use of the bees, for unless it is quite pliable the bees will reject it. =Excluder Zinc.=--It is impossible to work the bar-frame hive for profit without the aid of excluder zinc, for it is this useful appliance which prevents the queen from entering the supers and spoiling the surplus honey by laying her eggs in the comb. For the novice must learn at once that no honey should be extracted from combs which contain brood. The queen excluder should completely cover the open space above the brood nest before the super is placed over it. _A new queen excluder_ is now on the market, made of hard wires strapped together, and the patentee claims that more workers can pass through it than is possible with the old type. [Illustration: A Standard Frame with Drawn-out Comb] [Illustration: An Efficient Queen Excluder] [Illustration: A Frame Hive with the top removed]