But there is another and a kindlier explanation of the term, which rests on the authority of Constable, the painter, according to Yarrell, in his _History of British Fishes_, when writing of the Bullhead. ‘The head of the fish is smooth, broad, and rounded, and is said to resemble exactly the form of a miller’s thumb, as produced by a peculiar and constant action of the muscles in the exercise of a particular and most important part of his occupation. It is well known that all the science and tact of a miller are directed so to regulate the machinery of his mill that the meal produced shall be of the most valuable description that the operation of grinding will permit, when performed under the most advantageous circumstances. His profit or his loss, even his fortune or his ruin, depend upon the exact adjustment of all the various parts of the machinery in operation. The miller’s ear is constantly directed to the note made by the running-stone in its circular course over the bed-stone, the exact parallelism of their two surfaces, indicated by a particular sound, being a matter of the first consequence; and his hand is as constantly placed under the meal spout to ascertain, by actual contact, the character and qualities of the meal produced. The thumb, by a particular movement, spreads the sample over the fingers; the thumb is the gauge of the value of the produce, and hence have arisen the saying of _worth a miller’s thumb_, and _an honest miller hath a golden thumb_, in reference to the amount of profit that is the reward of his skill.’ Any notice of flour would, of course, be valueless without an analysis of its constituent parts, which, as anyone can understand, will vary in different wheats; there can be no standard, because of the difference of the soils on which it grows, a fact which is fully borne out by the following tables by famous analysts. Jago (_The Chemistry of Wheat, Flour, and Bread, &c._ Brighton, 1886), quoting Bell, says:—