substance which the bees use, chiefly in summer to
construct a sort of curtain between the entrance and the hive, is
called _propolis_, and by the same name is used by physicians in
making plasters: by reason of which use it sells in the Via Sacra for
more than honey itself. That substance which is called _erithacen_,
and is used to glue the cells together, is different from both honey
and _propolis_: it is supposed to have a quality of attraction for
bees and is accordingly mixed with bee balm and smeared on the branch
or other place on which it is desired to have a swarm light. The comb
is made of wax and is multicellular, each cell in it having six sides
or as many as nature has given the bee feet. It is said that bees do
not gather from the same plants all the materials which enter in these
four substances which they manufacture, namely: propolis, erithacen,
wax and honey. Thus from the pomegranate and the asparagus they gather
food alone, wax from the olive tree, honey from the fig, but not of
good quality: other plants like the bean, the bee balm, the gourd and
the cabbage serve a double purpose and yield both wax and food: while
the apple and the wild pear serve a similar double purpose but for
food and honey and the poppy again for wax and honey.

"Others again provide material for three purposes, food, honey and
wax, such as the almond and the charlock.[215] In like manner there
are flowers from each of which they derive a different one of these
substances, and others from which they derive several of them: while
they make distinctions in respect of plants according to the quality
of the product they yield,--or rather the plants make the distinction
for them--as with respect to honey, some yield liquid honey, like the
skirwort,[216] and others thick honey like the rosemary. So again honey
of insipid flavour is made from the fig, good honey from clover, and
the best of all from thyme.

"And since drink is part of a bee's diet and water is the liquid they
use, there should be provided near the stand a place for them to
drink, which may be either a running stream or a reservoir not more
than two or three fingers deep in which bricks or stones are placed
in such a way as to project a little from the water, and so furnish
a place for the bees to sit and drink; but the greatest care must be
taken to keep this water fresh, as it is of high importance to the
making of good honey.

"As the bees cannot go out to dist