294 British Association for the Advancement of Science. 



land, and the United States. The dependence of the velocity of the 

 tide wave on the depth of the ocean channels was pointed out as an 

 instance of the collateral benefits arising from the advancement of 

 any one branch of knowledge; for, in consequence of the perfection 

 of this branch of hydraulical science, it might be possible for geo- 

 logists to acquire some valuable information concerning parts of the 

 ocean where no plummet ever sounded and no line was ever cast. 



Mr. Babbage explained his views of a method of natural chrono- 

 metry derivable from an examination of the annual layers of growth 

 in wood. Considering these layers as liable to vary in thickness 

 according to favourable or unfavourable seasons, and any series of 

 them in one tree capable of being coordinated with a contempora- 

 neous series in another, by means of these irregularities, it was 

 shown to be possible to arrive at an accurate knowledge of the age 

 of trees in which life had become extinct, or which had been long 

 enveloped in peat bogs, provided a sufficient number of trees of in- 

 termediate ages, which had been subject to the same irregularities 

 of annual growth, could be examined. The bearing of the inquiry 

 on historical records of seasons and on geological speculations was 

 pointed out, and the process which it would be most convenient to 

 pursue in the application of the method clearly indicated. 



Professor Sedgwick presented a general review of the labours of 

 the geological Section during the week, illustrated by a section of 

 the Cumbrian and Silurian systems of rocks*. 



Dr. Lardner delivered a lecture on locomotive engines, illustrated 

 by drawings and working models. 



Dr. Barry gave an account of his ascent of Mont Blanc in 

 1834, illustrated by drawings. 



Mr. Babbage described a particular phenomenon in the sea on 

 the coast of Cephalonia (communicated to him by Lord Nugent), 

 which appeared to indicate the existence of a large cavity below the 

 bed of the sea, and communicating therewith. 



Professor Wheatstone exhibited his speaking machine, and ex- 

 plained the principles of its construction, and the progress which 

 had been made in the mechanical imitation of the human voice. 



Notices and Abstracts of Miscellaneous Communications to 

 the Sections. 



MATHEMATICS AND PHYSICS. 



Professor Hamilton gave a sketch of his new theory of logologues 

 and other numbers of higher orders ; (see Transactions of the Royal 



* A synopsis, by Mr. Murchison, of the formations included by him in 

 the Silurian system, was published in our number for July, present vol., 

 p. 46. — Edit. 



