46 THOMAS MACFARLANE: NOTE ON ZINC SULPHIDE. 
have arranged a scale of tints by comparison with which the “ body ” of any pigment may 
be very closely arrived at. The preceding table shows the composition of the various 
shades of blue constituting the scale, their numbers, and the names of the ordinary pig- 
ments of commerce with whose ascertained covering powers they correspond. 
In drawing attention to the covering power of Zinc sulphide, I have not, of course, 
attempted to discuss the nature of this property itself. As it is of considerable importance 
in the arts, its investigation seems worthy the attention of chemists and physicists. 
