viii 



In 1887 the west end of the house was set back a few 

 feet ; the staging was partly re-arranged and the broad 

 path through the transept was made. 



The humid conditions necessary for the cultivation of 

 tropical ferns are unfortunately not conducive to the 

 preservation of the structures in which they are grown 

 when they are built of wood. In 1889 it therefore again 

 became necessary to renew the east wing of No. II. House. 

 In order to secure greater durability it was decided to use 

 iron for the principal framework, and wood only for the 

 lights. The top ventilation was provided for by means 

 of a lantern in&tead of by the older and more clumsy 

 method of sliding sashes. At the same time the use of 

 green glass in the reconstructed wing was abandoned 

 This was introduced at Kew in 1846 on the recommenda- 

 tion of the late Mr. Robert Hunt, F.R.S., who advocated 

 its use on theoretical grounds which are now known to be 

 mistaken. The resulting improvement in the growth of 

 the plants, especially the species of Adiantum was very 

 marked, and in 1892 a portion of the west wing was 

 re-glazed with equally satisfactory results. 



The temperate ferns are now collected in a house 

 (No. HI.), which was also built on the system of mixed 

 iron and wood construction. It was erected in 1892 to 

 take the place of a decayed and obsolete structure com- 

 posed of two small greenhouses united together, Nos. 4 

 and 5 of Dr. Lindley's report. The former (the northern 

 wing) was erected in 1803, and in 1840 contained New 

 Holland and Cape plants ; the latter, which was " re- 

 modelled " in 1825, was filled with succulents* 



