I tried the thing in gold, silver, lead, glass, sand, common salt, wood, water, and wheat.
I provided two wooden boxes, round and equal: I filled the one with wood, and suspended an equal weight of gold (as exactly as I could) in the centre of oscillation of the other.

The boxes hanging by eleven feet, made a couple of pendulums exactly equal in weight and figure, and equally receiving the resistance of the air.

And, placing the one by the other, I observed them to play together forward and backward, for a long time, with equal vibrations.

And therefore the quantity of matter in gold was to the quantity of matter in the wood as the action of the motive force (or vis motrix) upon all the gold to the action of the same upon all the wood--that is, as the weight of the one to the weight of the other: and the like happened in the other bodies.

By these experiments, in bodies of the same weight, I could manifestly have discovered a difference of matter less than the thousandth part of the whole, had any such been.