Chemistry in golden era:

Chemistry In the field  of metallurgy  too  we notice some remarkable developmenk. Before the close of the sixteenth century, zinc was isolated by a process known neither to the Arab civilisation nor to the Europeans who learnt the art in  the early nineteenth century.  It has now been suggested by archaeological excavations at Zawar  in Rajasthan  that  Indians knew how  to isolate zinc by about the first century after Christ.  In China, zinc was isolated only during the ninth century.  

The isolation of zinc was accompanied by another achievemenf namely the manufacture of brass, an alloy of copper and zinc. Abu'l Fazl gave three proportions of  zinc and copper for obtaining brass of different varieties. Tin-coating of copper and brass learnt from the Arab world became prevalent in medieval India, thereby enabling copper vessels to be more widely used. Soldering, particularly of gold on agates, crystals and other brittle materials, was done so efficiently,  as to earn commendation from European  travellers. India seems to have discovered the freezing mixture before Europe. Saltpetre (potassium nitrate) was used  for cooling water before 1580. This discovery has been attributed to Emperor Akbar.