SECTION III, 1882 [ 45 ] Trans. Roy. Soc. CANADA. 
Note on Zine Sulphide 
By Tomas MACFARLANE. 
(Read May 27, 1882). 
I desire to call the attention of the Society to a peculiar property of anhydrous Zine 
sulphide. It possesses in an extraordinary degree the opacity and divisibility which, com- 
bined, make up the property known to manufacturers of pigments and painters as “ body” 
or covering power. Heretofore it has been supposed that no substance could exceed 
sesquibasic Carbonate of Lead (common white lead) in this respect, but I have ascertained 
that anhydrous zinc sulphide far excels it in covering power. 







| 
ee ae) | ee | peter COE er aren 
1 | iT 1 | Light sky blue. Zinc sulphide. 
2 | 1 2 Darker than foregoing. 
| 1 3 | Still darker. | N. P. white. 
| f Pure white lead. 
4 4 | do À Pure zine oxide. 
5 1 5 do St. Lawrence white. 
6 1 6 | do Ordinary brands white lead. 
| 
7 | 1 7 do Philadelphia sublimed lead. 
| 
8 | 1 8 | do 
Inferior brands of white 
9 | 1 | 9 | do { lead. 
| | Lighter than ultra 
10 1 | 10 marine blue. } Do 



Such substances as sulphate of Barytes and Carbonate of Lime which are used for the adulteration of white 
lead are very low in covering power, possessing only one-fortieth of the body of Zine Sulphide. 
The ordinary practical way of testing the “body” of a white pigment is to mix it in 
oil with an equal weight of any standard colour and then spread the resulting paint on 
glass. The lighter the tint, the more the white pigment is capable of masking the 
coloured one, and the greater is the “body” of the former. According to this test, zinc 
sulphide has the greatest covering power of any known substance and indeed four times 
that of white lead. 
On account of its immense body, zinc sulphide may be used as a standard for deter- 
mining covering power. By mixing it with various proportions of ultramarine blue I 
