That this _stannum_ was employed as an article of commerce, and that the ancients made of it vessels of various kinds, cannot be doubted. The _vasa stannea_ however may be considered as vessels which were covered with tin only in the inside; for that this was customary I shall prove hereafter. In general, these _vasa stannea_ are named where mention is made of saline or oily things, or such as would readily acquire a taste and smell from other metals, were they boiled or preserved in them for any length of time[515]. It has been long ago remarked that most of the Roman vessels were made of copper, and that these people were acquainted with the art of tinning or silvering them; but that tinned vessels have never been found, and silvered ones very rarely. Hence so many things appear to have been made of what is called _bronze_, which is less liable to acquire that dangerous rust or oxide, known under the name of verdigris, than pure copper. This bronze is sometimes given out as Corinthian and sometimes Syracusan brass, as the gold-coloured coins of the first size were considered to be Corinthian brass also. But in my opinion, a great and perhaps the greater part of all these things were made of _stannum_, properly so called, which by the admixture of the noble metals, and some difficult of fusion, was rendered fitter for use than pure copper. We are told by Suetonius, that the emperor Vitellius took away all the gold and silver from the temples and substituted in their stead _aurichalcum_ and _stannum_[516]. Whether the Greeks worked _stannum_, and under what name, I do not know: perhaps we ought to class here the κασσιτέρινα of the oldest times, of which I shall speak hereafter. What I have already said in regard to _werk_ will be rendered more certain by the circumstance, that even two centuries ago, vessels of all kinds called _halbwerk_ were made of it in Germany. This we are told by Encelius[517] as a thing well-known in his time, which however I should wish to see further examined. I have searched in vain for this name in a great many works of the sixteenth century; but I have long entertained an idea, which I shall take this opportunity of mentioning:--Among the oldest church vessels I have seen some articles which I considered to be _vasa stannea_, I mean such as when newly scoured and polished had a silvery brightness, and when they remained long without being cleaned acquired a dull gray colour, and a greater weight than bronze. Those who show these things commonly say that the method of composing the metal is lost; but that it contains silver, and according to the assertion of many, even gold. Such articles deserve, undoubtedly, to be examined by our chemists.