The following historical advertisements appeared on page 41 of the original book. They are included for completeness.--JBH.
INSTRUMENTS FOR LEY-MAPPING.
Moveable head T squares with divided quadrant, also other special appliances supplied if a demand arises.
THE WATKINS MANUAL of Photographic Exposure and Development. 9th Edition (about 80,000 sold).
The only Manual I have read which seems to me absolutely simple and direct."--Westminster Gazette. (Post 3d.) 1s. 3d.
MUST WE TRADE IN TENTHS, being a plea against Decimal and for Octaval Coinage as more exactly fitting the wants and usage of all who make, grow, buy or sell things.
"A powerful plea."--Financier and Bullionist. (Post 1d.) 3d.
TWO LEAFLETS FREE FOR POSTAGE.
OCTAVAL NOTATION AND THE MEASUREMENT OF BINARY INCH FRACTIONS.
IDEAL PROPORTIONS AND SIZES FOR PRINTING PAPERS.
We were established in 1900 for the manufacture of Mr. WATKINS'S Exposure Meters and Development Aids in Photography. Also Dough Meters for household and trade bakers, and steel Octaval Rules.
Ask for Lists.
WATKINS' METER CO., HEREFORD.