350 FKENS : BRITISH AND FOEEIGN. 



summerj but taking care to prevent currents of dry air. 

 I liave now stated the chief points to be observed 

 in forming and arranging an indoor natural Fernery^ 

 the principles of which are capable of application to 

 houses of the ordinary construction and usual average 

 size, or- to any extent that means will allow j even to 

 realize the grand idea of the celebrated Loudon, who, 

 more than thirty years ago, speaking in favour of span- 

 roofs, said, " There would be no difficulty in covering 

 ten acres of Kew Gardens with glass by a series of 

 span-roofs." Although since then much has been 

 done at Kew, by the erection of lofty plant-houses, 

 still the area covered falls far short of ten acres ; but 

 as natural cultivation is now patronized, and with 

 the improving age and desire for novelty, let us, hope 

 that the time is not far distant when Kew may have 

 at least one acre converted into a straight or winding 

 Fern-valley covered with glass, the highest part not 

 to exceed thirty or thirty-five feet above the centre of 

 the valley, that being sufficient height for such Tree 

 Ferns as may perchance withstand the vicissitudes of 

 thirty years careful treatment. 



In a house of this kind, furnished with means of 

 maintaining a temperature of 60 in the coldest weather, 

 situations in it would be found suitable to the good 

 growth of not only F^rns and Aroidew, but also 

 liromeUaeece, Orchids, and other kinds of plants of an 

 epiphytal nature. 



For an open-air Fernery a sheltered situation should 

 be chosen, and if possible within the influence of 

 shelter and shade, but not under trees ; a sloping bank, 

 a natural or artificial hollow, such as an old gravel-pit 

 or sunk fence, may be turned to good account. The 



