COWS AND PHOTOGRAPHY

Timaru Herald, Volume CXLV, Issue 21210, 3 December 1938, Page 17

COWS AND PHOTOGRAPHY

SULPHUR FROM SALVES "So you see that If a cow didn’t like mustard we shouldn’t have any movies,” Dr. C. E. K. Mees said at the Royal Institution. It was the third of his lectures on photography; and his young hearers already knew so much about the chemistry of photography that they had no difficulty in swallowing this rather surprising proposition. They had learned that the probable reason why the gelatine used in photographic materials makes them so exceedingly sensitive to light Is that it contains a trace of sulphur, and the sulphur is derived from mustard oil. The gelatine is made from calf skins, and quite a lot of plants in meadows have mustard oil in them. Gelatine made from skins of other animals lacks the mustard. That, Dr. Mees suggested, may be because the other animals are more discriminating feeders. “A rabbit,” he said, "eats one blade of grass at a time. When it is a hot one the rabbit doesn’t eat it. A cow is like a mowing machine: it eats everything that comes, its way.” And that is why cows—or rather their calves—are in a position to supply the mustard oil which is indispensable in the camera.