Silver-tin and bismuth-tin alloys, by melting point?

Factual Questions
1

I have a silver and tin alloy that melts at 221 C, and a bismuth and tin alloy that melts at either 140 or 190 C (the digit is a little unclear but probably a “4”). How can I tell the ratio of the metals, from the melt point? Are these eutectics?

I hunted around for some web table or program that would give eutectics for various combinations of elemental metals but only found one here, two there, and not these. Is there a good web resource for this?

Thanks!

2

Ag-Sn is 3.5% by weight Ag, Bi-Sn is 58% Bi by weight and melts at 138 C.

3

Oh, nicely done, yoyodyne! Thank you!