‹‹‹ Vitr. 10.3.6 | Table of Contents | Vitr. 10.3.8 ›››
7Also, when loads of great weight are carried by porters in gangs of four or six, the levers are so adjusted in the middle that each porter may be loaded with a proper proportion of the burden. The middle parts of the levers for four persons over which the tackle passes, are provided with pins to prevent it sliding out of its place, for if it shift from the centre, the weight will press more on the shoulders of him to whom it is nearest, just as in the steelyard the weight is shifted towards the end of the beam.
7And when the heaviest burdens are carried on poles by four or six porters at a time, they find the centres of balance at the very middle of the poles, so that, by distributing the dead weight of the burden according to a definitely proportioned division, each labourer may have an equal share to carry on his neck. For the poles, from which the straps for the burden of the four porters hang, are marked off at their centres by nails, to prevent the straps from slipping to one side. If they shift beyond the mark at the centre, they weigh heavily upon the place to which they have come nearer, like the weight of a steelyard when it moves from the point of equilibrium towards the end of the weighing apparatus.