A measurement method of the tin content calculated based on the measurement of the transmittance ratio was proposed.

为此提出测量浮法玻璃在加热与不加热时的透过率比值来计算渗锡量的测量方法。

youdao

Tin content and petrochemical feature suggest that the granites and part of vein rocks are tin-bearing.

含锡量及岩石化学特征参数表明：矿田地洼花岗岩为含锡花岗岩，部份脉岩为含锡岩脉。

youdao

The content of the letter itself is not rare as it discusses income from tin mining stocks, at a time when the industry was still a driving force in Cornwall.

BBC: Rare Truro blue marked letter found in Exeter archive