409. The Germans have produced few original authors on gardening, and none that can be compared to Quintinye or Miller; but they have translations of all the best European books. Hirschfeld has compiled a number of works, chiefly on landscape-gardening; J. V. Sickler and Counsellor Diel have written extensively on most departments of horticulture, especially on the hardy fruits. In regard to apples and pears, the two most scientific writers on their classification are Manger (Anleit. zum einer Systemat. Pomol.) and Diel. The first takes form as the foundation of his arrangement; the second takes jointly the quality of the fruit and the peculiarities of the tree. Diel's system is, in our opinion, decidedly the best; in short, it is in pomology what the natural system is in botany. (Gard. Mag., vol.ii. p. 445.) Truchsess is the standard author on cherries, and Sickler on grapes and on the genus Citrus.