Another and still more eloquent fact will finally convince whoso may yet be doubting. The ration of honey stored up in a cell is evidently measured by the needs of the coming larva. There is neither too much nor too little. How does the Bee know when the proper quantity is reached? The cells are more or less constant in dimension, but they are not filled completely, only to about two-thirds of their height. A large space is therefore left empty; and the victualler has to judge of the moment when the surface of the mess has attained the right level. The honey being perfectly opaque, its depth is not apparent. I have to use a sounding-rod when I want to gauge the contents of the jar; and I find, on the average, that the honey reaches a depth of ten millimetres. (.39 inch.--Translator's Note.) The Bee has not this resource; she has sight, which may enable her to estimate the full section from the empty section. This presupposes the possession of a somewhat geometric eye, capable of measuring the third of a distance. If the insect did it by Euclid, that would be very brilliant of it. What a magnificent proof in favour of its little intellect: a Chalicodoma with a geometrician's eye, able to divide a straight line into three equal parts! This is worth looking into seriously. I take five cells, which are only partly provisioned, and empty them of their honey with a wad of cotton held in my forceps. From time to time, as the Bee brings new provisions, I repeat the cleansing-process, sometimes clearing out the cell entirely, sometimes leaving a thin layer at the bottom. I do not observe any pronounced hesitation on the part of my plundered victims, even though they surprise me at the moment when I am draining the jar; they continue their work with quiet industry. Sometimes, two or three threads of cotton remain clinging to the walls of the cells: the Bees remove them carefully and dart away to a distance, as usual, to get rid of them. At last, a little sooner or a little later, the egg is laid and the lid fastened on. I break open the five closed cells. In one, the egg has been laid on three millimetres of honey (.117 inch.--Translator's Note.); in two, on one millimetre (.039 inch.--Translator's Note.); and, in the two others, it is placed on the side of the receptacle drained of all its contents, or, to be more accurate, having only the glaze, the varnish left by the friction of the honey-covered cotton.