ON THE GEIIANIUM HOUSE. 277 



therefore a particular point is to be found to which the thermo- 

 meter may be allowed to sink in the inside of greenhouses during 

 a severe frost, will preserve the Geraniaceae from injury and not 

 produce too much heat for the safety of the heath, it is one which 

 I have never been able to ascertain. 



" I am speaking however, of these two families so as to have 

 them in a high state of perfection. They must be both kept in the 

 same house so as to make a tolerable appearance ; but I believe 

 not in such a state of perfection as if they were in separate houses; 

 for the fire heat which is absolutely necessary during severe frost 

 for the one, is, as far as my observation goes, sure to be in some 

 degree injurious to the other." 



Most of the Cape species are much hardier than the English 

 hybrids, for many of the former, particularly the tuberous-rooted 

 kinds, stand in the open borders of this country during winter, 

 while none of the latter, so far as we know, have ever been known 

 to do so. The same degree of cold that would not injure the most 

 tender Erica, would be fatal to the whole tribe of hybrid Gera- 

 raniums. 



During winter, frost must be excluded by covering the Gera- 

 nium house with canvass, or by the application of artificial heat 

 from the fire, either through smoke flues or hot water pipes, so 

 as to keep the temperature from falling below thirty-two degrees, 

 but it should by no means be allowed to rise by the same means 

 to forty degrees, a higher temperature during the day and by sun 

 heat, is quite a different thing. 



On the general treatment of Pelargoniums, we find the follow- 

 ing communication of Mr. Appleby in Vol V. of the Horticultural 

 Cabinet, so replete with good sense and practical skill, that we 

 cannot do better than give the quotation almost at length. 



" The season to take Geraniums into the greenhouse depends 

 upon the weather ; and as all Cape plants are much healthier, and 

 flower more freely the more they are exposed to the full air, so 

 long as frosts keep off, I delay the taking them in : in fact, this 

 last season, I did not house them generally until the middle of 

 October. Choice kinds I have covered up with mats or large sheets 

 of canvass, elevated on stakes, on such nights as are likely to be 

 frosty. 



"Perhaps no months in the whole year are so unhealthy for Ge- 

 raniums as November and December, for the weather generally is 

 dark, damp, and rainy, and the plants being full of sapy green 



