42 DT7BLIN NATURAL HISTORY SOCIETY. 



situations, have scarcely suffered, and the whole of the trees are growing 

 vigorously, Cedrus deodara proves to be quite hardy. The Laurustinuses, 

 bay trees, and the heaths. Erica Mediterranea, Australis, arborea, and vagans, 

 were killed to the ground, but are now growing freely. I fully expected all were 

 dead, as they were very late before they broke — Dropmore, Tith December, 

 1838." Time should be given to valuable plants apparently dead. The most 

 severe frost of the winter was the middle of January, 1838. In the island of 

 Jersey the coldest day was on the 19th, when Fahrenheit's thermometer, at five 

 o'clock p. M., was 18; on the 17th of the same month, it was noted, at the Nur- 

 sery in Kilkenny, that Fahrenheit's thermometer fell to 20. The magnolias, both 

 in England and on the Continent, suffered but little injury ; while the pines, 

 heaths, and rhododendra, extensively perished. A friend informs me that, at 

 the gardens at Cronstadt, St. Petersburgh, and Moscow, at the approach of 

 winter, all plants and vegetables are packed away, stored, and sheltered, and 

 throughout the winter the gardens present dreary scenes of desolation. At the 

 end of April the thaw hurries all into arrangement; and, with the vigour of the 

 sun, vegetation bursts forth like a thought; and, during the few months of 

 summer, the gardens are as gay as those in the neighbourhood of London. The 

 severity of a winter causes a corresponding heat in the ensuing summer, and 

 from the observations made by Mr. Erman (Humboldt, Asie Centrale), such 

 severe winters are followed by warm and dry summers. M. L. C. Seitz, Royal 

 Court and Botanic Gardener at Munich, remarks in the "Garten Zeitung," for 

 August, 1838, with reference to the severity of the winter of 1837-38 • — "We ex- 

 perienced an almost insupportable heat during the months of June and July, 

 when the thermometer continually varied between 23° and 25° of Reamur (80*» 

 to 85" Fahrenheit). On the 15th of July, at two o'clock in the afternoon, it was 

 260-25° Reamur (90' Fahrenheit) ." 



Mr. Robert Callwell observed that in his large fernery he had noted, 

 within the house, the thermometer to fall to 18". Neither Trichomanes nor 

 Adiantum Capillus Veneris suffered in the least. He attributed this to the 

 temperature being in some degree uniform, and to the stillness of the atmo- 

 sphere. 



JANUARY 16, 1851. 



ON THE TREATMENT OF TRICHOMANES RADICANS UNDER CULTURE. 

 BY ROBERT CALLWELL, M. R. I. A. 



(Abstract.) 



The statements he was about to make were upon the successful results 

 of his several modes of treatment of the cultivation of that beautiful fern 

 (T. radicans). In the year 1842 Mr. Andrews had given him a plant having 

 two fronds — one about six inches in length, the other partially developed. These 

 he placed under a bell-shaped glass shade, which was about fifteen inches in dia- 

 meter and eighteen inches in height. The fern was planted in pure maiden 

 earth, or virgin mould, a good drainage being formed by placing inverted flower- 

 pots in the receiver. Through this mould he interspersed portions of charcoal. 

 The temperature and moisture was carefully regulated, although but little 

 watering was given to the plant. Great care was taken to keep the growing 

 fronds from contact with the glass, for so delicate and sensitive were the beauti- 

 ful fronds when expanding, that, should they rest against the glass, they become 

 blackened and unsightly. In the spring of 18-15, so luxuriantly had the plant 

 extended, that he removed the mass to a larger case. At that time there were 

 about twenty fronds, all fully developed, and presenting that beautiful green hue 

 and delicacy of texture which are the remarkable characteristics of the plant. 

 The new habitat was a framed case of neat mahogany, glazed on all sides, and 



