These disadvantages, except that of expense, are overcome by incorporating fine wire in the sheets of foundation when they are rolled. The sheets are trimmed with wooden shears, which leave the ends of the wires projecting. These are then glued to the bars of the frame. The added expense is again the main objection, except to those who wish to ship colonies or nuclei, or transport them from place to place for pasturage. COMB-FOUNDATION MACHINES. The first attempts to give bees outlines of cells as a basis for comb building were made in Germany. The top bars of the frames were coated on the underside with beeswax, and a strip of wood having the outlines of bees' cells cut on it was then pressed against this wax so as to form a guide which should lead the bees to build their combs within the frames. This was only a comb guide, but was succeeded by small strips of wax having the outlines of bees' cells pressed on them by hand, a block of wood being engraved for this purpose. The general use of comb foundation, especially of the full sheets, was only made possible through the improved means of manufacturing it developed in the United States. The slow process of hand stamping was succeeded by its rapid production on machines, the essential feature of which is two engraved cylinders between which the warm sheet of wax is made to pass (fig. 43). [Illustration: Fig. 43.--Comb-foundation machine. (From Langstroth.)] Such machines are now made in numerous patterns costing from $15 up. Foundation is made with flat-bottomed cells and also with the same form as that given by the bees to combs constructed wholly by themselves. Both sorts are readily accepted by the bees and built out. Both these kinds are also made in various qualities and weights. Only a good quality of perfectly pure beeswax should be accepted. Brood foundation is made in light, medium, and heavy weights. For use in section boxes thin surplus and extra thin surplus are made of light-colored wax. When full sheets are used in sections it is better to have it extra thin lest there should be a noticeable toughness of the midrib, technically known as "fishbone." For unwired frames the medium or heavy brood-comb foundation should be employed. Until used it is best to keep comb foundation between sheets of paper and well wrapped, since if long exposed to the air the surface of the wax hardens somewhat, but if well packed it may be used years after it was made with almost the same advantage as when first rolled out.