MISCELLANEA. 



RECTIFICATION ON THE SUBJECT OF THE SKIMMIA JAPONICA. 

 In our account of this beautiful evergreen shrub, at page 6 of the present volume, we stated, on 

 the authority of Dr. Lindley, that it was identical with a Himalayan plant described by Dr. Wallich 

 under the name of Limonia Laurcola. "We have since learned that the SMmmia japonica of Messrs. 

 Standish and Noble is quite distinct from that from the north of India ; the two plants both 

 belong, however, to the same genus, Skimmia laureola being now substituted b ; Dr. Lindley for the 

 former name of the Himalayan species. This latter, although introduced some years since, has never 

 yet flowered, whilst the Skimmia japonica blossoms freely when only two inches high, and fruits at 

 six inches, as we stated in our article. The two species may be readily distinguished by their 

 leaves; those of S. japonica are, as our figure shows, 'lanceolate, rather wavy, and acuminate'; those 

 of S. Laureola (alias Limonia Laureola) are of a flatter farm, pointed, but less tapering; the scent of 

 the foliage is also distinct — that of japonica emits, when bruised, an apple-like fragrance, but in 

 Laurcola the scent resembles that of Rue and Fraxiuella. The rectification of the error is of some 

 importance, as we gather from Messrs. Standish and Noble's communication to Dr. Lindley in 

 Faxton's Flower Garden, that some Nurserymen are selling 8. Laureola for the S. japonica, a substi- 

 tution which, if iguorantly made, woidd not the less cause great disappointment to the purchaser. 



APPLICATION OF ERICSSON'S 'REGENERATOR' TO THE VENTILATION OF 



GREENHOUSES. 



Although the E. F. G. is addressed chiefly to those who are presumed to be without a greenhouse, 

 we think it quite probable that the following communication of a highly respected friend may 

 prove interesting to many readers, on account of the principle involved. The due ventilation of 

 plant houses is justly regarded as one of the most important points in their management, supplies of 

 fresh air being indispensable to a healthy and vigorous vegetation among all but Cryptoganric plants. 

 During the summer months this can be afforded without difficulty, but in the winter and spring 

 seasons, the incautious admission of cold air from the exterior is often attended with an injurious 

 reduction of temperature. This is sometimes prevented by allowing air to enter only by apertures 

 over the flue surrounding the house, by which it is warmed before coming into contact with the 

 plants, but even where this arrangement exists, it is probable that other ventilators might be 

 employed with advantage, when the external temperature is not sufficiently low to render fire-heat 

 necessary. What follows we give in our correspondents own words. 



' It is with theview of realising the important floricultural desiderata above mentioned (of fresh air, unac- 

 companied by too great a reduction of temperature), that I am induced to propose the application to such 

 buildings, of the very simple and beautiful philosophical contrivance which is now so well known, on account of 

 its intimate association with the Caloric Sliip, and which has been called by Ericsson the "Regenerator." It 

 consists of a number of lamina of fine copper or iron gauze, placed in opposition, so as to constitute any 

 required thickness; Ericsson employing a thickness of afoot, or foot and-a-half, for the series which form 

 the " Regenerator" of his Caloric-Engines. Much fewer plates would, however, suflice for the purpose to 

 which 1 refer; indeed, not more than a hundred united lamina of moderately fine copper-gauze would, I 

 conceive, lie required. Now, the principle of the " Regenerator " is simply this':— the heated air in passing 

 through the innumerable interstices presented by the metallic nettings becomes robbed of the whole, or nearly 

 the whole of its caloric : whereas, the cold air entering to supply its place, takes up or receives the amount of 

 heat previously thus abstracted, and consequently, but a very small quantity disappears, or is practically lost. 

 Nqqiose then, the roof of a greenhouse to be fitted with such a " Regenerator," and it follows, that while 

 sufficient air might be admitted to afford the necessary ventilation, an equal temperature would also be 

 established in the building. For as it has just been stated, the heat lost by the air in passing out, would 



