LEAVES THEY HAVE TOUCHED, 151 



will have tlie kindness to send me any details ■which yon think fit, on 

 your proposed method of correcting the compasses of iron ships, 1 

 shall be glad to consider them, and as opportunity serves, -will report 

 to you on them. I presxime that I am not to understand literally, 

 your expression, ' needles can be and are insulated from the local 

 influence of iron ships and ships' iron"? I am, sir, your obedient 

 servant, G. B. Airy." (2.) Two notes from the hand of Sir John 

 F. W. Herschel, author of the well-known " Discourse on Natural 

 Philosophy," and foi'merly Fellow of St. John's College. Both of 

 them are characteristic. One is addressed to some gentleman who 

 has asked him to join an expedition to a cavern at Maidstone, where 

 the remains of hyenas are found. His occupations and engagements 

 oblige him to decline. In like manner he was not able on Friday 

 last to attend a meeting of the Geological Society ; and that evening 

 he was to be by appointment with Mr. Sande at the Observatory of 

 Camden Hill, where he expects they will make a night of it. The 

 other is addressed to Professor Faraday in 1827. It contains a 

 scheme for a series of scientific experiments to be made by him, and 

 reported on periodically. In this note, the Observatory at Slough is 

 mentioned, from which Herschel desires to be as little absent as 

 possible, so long as the state of the moon permits him to continue 

 his observations. («) " 2nd June, 1827. — Dear Sir : I am sorry I 

 can't go on the very interesting expedition to the Hyeniferous 

 Cavern at Maidstone. I am no less sorry I coidd not attend at the 

 Geological Society on Friday ; and to-night am going to make the 

 second observation at the Observatory at Camden Hill, according to 

 promise. Mr. Sande made the first last night, which decided a point. 

 I suppose -we shall make a night of it. Yours truly, J. F. W, 

 Herschel." (6) "Devonshire Street, Tuesday, November 6th, 1827. 

 Dear Sir : I received yesterday, too late to allow me an opportunity 

 of seeing you before your leaving town, your note dated the 3rd. I 

 am glad to hear the furnace and other preparations are in a state of 

 forwardness, and when you return, hope the expedition will com- 

 mence. I directed Mr. Hudson to forward to you the report of the 

 third experiment in the Glass-house ; that and the committee books 

 will put you in possession of all that has been done, (together with 

 your own recollection of what has passed under your own eyes.) On 

 Saturday, the 10th, my astronomical pursuits call me to Slough, 

 whence I am to be desirous to be as little absent as possible, so long 



