How Does Von Leebig Connect Back to Mirrors?

In 18 35, eustace von leebig also discovered a process for making metal backed glass mirrors in a way that wouldn't be nearly as hazardous to the health of the workers. He began by applying silver nitrate in a solution of ammonia to the back of the glass and then exposing that to fumes of formaldahide. In 18 56 he came up with te with another improved method of doing this. And manufacturers eventually found that the layer of silver could be acted by covering it with layers of paint and varnish. But anywayso how does von liebig connect back to mirrors? Well, remember that the problem is with the mercury exposure that the workers are facing on these