LEAVE OF ABSENCE. . 125 



and I can truly say, when I scolded you, as you call it, it was 

 more in sorrow than in anger. The society of the circle you 

 mention must be very pleasant. It is a great privilege to be 

 thrown into a group of superior minds, and their conversation 

 will supply the want of your full indulgence in your favourite 

 study. Many thanks for your extract from " Salmonia," which I 

 have transferred to my Bible according to your hint. It is very 

 beautiful and new to me, for though I am well acquainted with 

 the " Consolations," I have, strange to say, never read the 

 " Salmonia." Of the " Consolations," I like " Proteus " the best. 

 I think Sir Humphry would have been a great poet, if he 

 had cultivated the talent. It is said that Coleridge used to 

 attend his lectures, not from taking an interest in the subject- 

 matter, but for the sake of the felicitous illustrations that flashed 

 from him continually. 



I paid a last visit (not the last, I hope) to your fern-house on 

 Thursday, and think I never saw it looking so well. It will be 

 long before the walls of mine are so beautifully covered. 

 I must send you a large Hemitelia. I intend sending several, 

 as tall as will fit in the cases I am taking out. 



I opened a book yesterday called " Fact Book for 1840," or 

 some such name. The first botanical fact stated was " Plants 

 grown without air," by Mr. Ward. Can you tell me, is it a 

 fact ? There is an experiment much in your way, which, if it 

 could be tried, would be an important one ; but I fear it is im- 

 practicable. It is whether plants exposed to no other light 

 than what are called the chemical rays, which you know are 

 invisible, would grow green or any other natural colour, or 

 whether they would be white, as if grown in total darkness. 

 Do you think one could contrive it, and what would be the best 

 plants for experiment ? As we have constant sunlight at the 

 Cape, I could perhaps manage it there. The point I want to 

 throw light on is the colours of Algse at great depths of the sea 

 — where common light is entirely intercepted, but where per- 

 haps these chemical rays may penetrate. If we could prove 

 that they were sufficient to cause perfect colours in vegetables — 

 as is probable, seeing they seem to be the most active in 

 properties — one might infer that they were the colouring 

 agents in " those dark unfathomed caves." If you think 

 the experiment worth anything, please, at your leisure, send 



