174 A. W. Wright—Electrical Deposition of Metals. 
surfaces very easily, and a mirror of the most perfect surface 
produced at once, without the necessity of a single touch to 
complete it. Several such mirrors have been made in the 
course of these experiments, by the use of concave glass lenses, 
with the most satisfactory results) The metal film adheres 
strongly to the glass, and when of sufficient thickness appears 
to be very firm and hard. In mirrors silvered by the ordinary 
method, trouble is often experienced from the insinuation of 
moisture between the glass and the metal, resulting finally in the 
separation of the latter. In those prepared by the new process 
the adherence of the film is so close as to render such an effect 
impossible. As a test of this, a small silvered speculum was 
placed in a beaker of water where it remained for two weeks, 
and besides this was wetted and dried repeatedly, without 
‘ showing the slightest tendency to suffer the penetration of the 
moisture. Similar resuits were also obtained with platinum 
The metallic luster was wanting, though it was readily devel- 
oped when a portion of the powdery coating, which was easily 
removed, was rubbed against the surface of the glass with some 
pressure. The defect was, to a considerable extent, remedied 
by surrounding the electrode with a small glass tube proce 
some three millimeters beyond it, so as to clear the surface 
