Point X

Pewterers may harden their Tin or Pewter, and give to it an elegant whiteness, so that it will resemble Silver both in colour and sound; neither will it easily tarnish, and by reason of its hardness, will last longer than common Pewter.

If Tin be often melted, and extinguished in a lixivium of fixt Nitre, it is made harder than it was before; but if it be put to Nitre in Flux, and suffered to melt in it; then also it will be more hard. NB. But if the Tin be reduced into Scoria by Nitre, and the Scoria again reduced, it will be rendered harder and fairer, than by the two former ways.