ADHESION OF PLANE SURFACES. 155 



Extract of a tetter from a distinguished individual in Ireland, dated 

 February 27, 1828. 



" I have lately heard a curious fact respecting soms American 

 timber ; 1 believe, Canadian pine ; but of this I am not certain, as 

 the words used by the person who told me the anecdote were 

 general, viz : American timber. 



" A person of our acquaintance had 36 dozen of wine in bottles, 

 packed in Dublin in sawdust of American timber. The sawdust, 

 when the wine was unpacked, was found swarming with an insect 

 which had eaten through the corks of several of the bottles — the 

 wine was spilled, and the bottles filled with the insects ; all those 

 of which the corks were yet safe, the person was obliged to have 



new-bottled. I mentioned this fact to Mr, , a great Dublin 



coach-maker, to whom I had occasion to write at the time, and to 

 whom I thought it would be useful — he answered in these words : 



" ' I had heard before of the insect you refer to in the sawdust 

 of American timber, and in the timber itself there is a much great- 

 er grievance. I understand there are whole streets in London 

 lately built, in which this timber has been used, and rendered al- 

 most unfit for habitation by the cimex (I believe) axanthia, which 

 actually swarms in the crevices of the joints, &lc, and cannot be 

 removed by any thing short of conflagration.' " 



" I wish you would let me know if there be any complaint of any 

 particular kind of timber in America as being infested with this in- 

 sect. If the fact be as stated, the kind of limber should be dis- 

 tinctly described, for avoidance, else the general report will affect 

 the credit of all American timber. Is there no remedy ? Pray in- 

 quire, and make your answers more distinct thap I have made my 

 questions." E, 



Plane Surfaces not separated by a Blast, in certain cases, 



Wallingford, Vt, May 16, 1828. 



TO PROF, SILLIMAN, 



Dear Sir, — I beg leave to call your attention to a fact, for the 

 explanation of which a gold medal and one hundred guineas were 

 offered by the Royal Society. 



The experiment is this : cut from a card two pieces about two 

 inches in diameter, let one of them be perforated in the centre, 

 and let a common quill be introduced into the perforation, with 

 one end even with the surface of the card — let the other piece of 

 card be made a little convex, and lay its centre over the end of the 

 quill, with the concave side of the card down — the centre of the 

 upper card should be from l-8th to l-4th of an inch above the end 

 of the quill. On attempting to blow off the upper card, by blow- 

 ing through the quill, it will be found impossible. 



I prepared the pieces of card very carefully, according to dircc^ 

 tioq, and to my astonishment, the upper card could not be blozvn ojf. 



