To shoot your arquebus precisely the end of the breech must come precisely on the edge of the light, because like this the powder catches [fire] and burns all at once without blowing and has more strength and does not recoil. On the contrary, if the breech is made hollow, as they commonly are, the powder catches more quickly in this place, makes it recoil, and blows. This is clearly shown [by] a arquebus with a chamber which recoils more than another. And since the cannon is bigger at the breech than at the muzzle the sights are also uneven, because that at the breech is higher than that at the muzzle. Additionally, the thickness of the cannon is greater than the caliber by about one line, and the sight by another. It would therefore be necessary to either make the cannon all of one size or to raise the barrel from the end and towards the muzzle, and push it in and lower towards the breech. The weight of the powder must be one third of the [weight of the] bullet.