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of flowers. The petals of fresh flowers are carefully selected, and crushed to a pulp in a marble mortar, either alone or with the addition of a little alcohol, and the juice expressed by squeezing the pulp in a clean linen or cotton cloth. It is then to be spread upon paper with a flat brush, and dried in the air without artificial heat. If alcohol be not added, the application on paper must be performed immediately, as the air (even in a few minutes), irrecoverably changes or destroys their color. If alcohol be present this change is much retarded, and in some cases is entirely prevented. Most flowers give out their coloring matter to alcohol or water. Some, however, refuse to do so, and require the addition of alkalies, others of acid, &c. Alcohol has, however, been found to enfeeble, and in many cases to discharge altogether these colors; but they are, in most cases, restored upon drying, when spread over paper. Papers tinged with vetegable colors must always be kept in the dark, and perfectly dry. The color of a flower is by no means always, or usually, that which its expressed juice imparts to white paper. Sir John Herschel attributes these changes to the escape of carbonic acid in some cases; to a chemical alteration, depending upon the absorption of oxygen, in others; and again in others, especially where the expressed juice coagulates on standing, to a loss of vitality, or disorganization of the molecules. To secure an eveness of tint on paper, the following manipulation is recommended:--The paper should be moistened on the back by sponging and blotting off. It should then be pinned on