167r - - - - - Mortars
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Mortars are made of the best alloy of métal and the finest possible rosette so that they do not burst, that is to say one part métal and two parts fine rosette or old caudron, which is even better. Some of them are of fifteen or seventeen lb. and are loaded with two and a half lb. of grain powder, and they are put on common windows and doors. Others are of a weight of 25 to 27 lb. and are loaded with eight lb. of powder. And in such a way, they are made according to the stress they have to resist. On the outside, they are all the same shape, but in the inside, they are made like a crucible,
Figure
narrower on the inside of the bottom and getting wider towards the mouth. And this is to reinforce the bottom, given the quantity of powder they hold, and so that they do not burst. Those of 4 s. lb. are eight lignes thick at the bottom, and get thinner in the inside towards the opening, which is of 4 lignes. They have xiii poulsses long and seven in diameter at the mouth and opening.
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