Mercury Bath

Fig. 13 gives a front view of the mercury bath now in general use in this country for mercurializing and bringing out the picture. It is quite an improvement on those first used. To make it more portable it is in three pieces, a b and c; having a groove e on one side to receive the thermometre tube and scale by which the proper degree of heating the mercury is ascertained. Into the top are nicely fitted two or three iron frames, with shoulders, for the plate to rest in, suitable for the different sizes of plates. The bath is heated by means of a spirit lamp placed under it. From two to four ounces of highly purified mercury are put into the bath at a time.