THE LONGEVITY OF TREES. 77 



houses,' in 1805, and on ' Country Residences,' in 1806, both 

 4to ; ' Hints on the Formation of Gardens,' in 1812 ; and 

 three works on « Hothouses,' in 1817 and 1818. In 1822 ap- 

 peared the first edition of the ' Encyclopaedia of Gardening ' ; 

 a work remarkable for the immense mass of useful matter 

 which it contained, and for the then unusual circumstance of 

 a great quantity of woodcuts being mingled with the text : 

 this book obtained an extraordinary sale, and fully established 

 his fame as an author. Soon after was published an anony- 

 mous work, written either partly or entirely by Mr. Loudon, 

 called the * Greenhouse Companion ' ; and shortly afterwards, 

 1 Observations on laying out Farms,' in folio, with his name. 

 In 1824, a second edition of the ' Encyclopaedia of Garden- 

 ing ' was published, with very great alterations and improve- 

 ments ; and the following year appeared the first edition of 

 the ' Encyclopaedia of Agriculture.' In 1826, the ' Gardeners' 

 Magazine ' was commenced, being the first periodical ever de- 

 voted exclusively to horticultural subjects. The ' Magazine 

 of Natural History,' also the first of its kind, was begun in 



1828. Mr. Loudon was now occupied in the preparation of 

 the ' Encyclopaedia of Plants,' which was published early in 



1829, and was speedily followed by the ' Hortus Britannicus.' 

 In 1830, a second and nearly rewritten edition of the • Ency- 

 clopaedia of Agriculture ' was published, and this was followed 

 by an entirely rewritten edition of the ' Encyclopaedia of 

 Gardening,' in 1831 ; and the ' Encyclopaedia of Cottage, 

 Farm, and Villa Architecture,' the first he published on his 

 own account, in 1832. This last work was one of the most 

 successful because it was one of the most useful he ever wrote, 

 and it is likely long to continue a standard book on the sub- 

 ject of which it treats. Mr. Loudon now began to prepare 

 his great and ruinous work, the ' Arboretum Britannicum,' 

 the anxieties attendant on which were, undoubtedly, the 

 primary cause of that decay of constitution which terminated 

 in his death. This work was not, however, completed till 

 1838, and in the mean time he began the ' Architectural 

 Magazine,' the first periodical devoted exclusively to archi- 

 tecture. The labor he underwent at this time is almost in- 



