145 



and the instruments employed in these experiments were exhi- 

 bited in action before the Academy. 



The author made some remarks as to the unexpected slow- 

 ness of transit of these pulses, and ascribed deficiency of velocity 

 as predictable from the theory of elastic moduli, as probably 

 due to the imperfect homogeneity and continuity of the media 

 operated on. The relation that his results bore to those re- 

 cently obtained as to the rate of sound in wrought iron, as de- 

 termined in France, suggested that the hitherto received theory 

 of sounds in solids would probably require to undergo revision. 



Sir William Betham read a paper on the account of Thomas 

 de Chaddisworth, Custodee of the Temporalities of the Arch- 

 bishop of Dublin, from 1221 to 1256, from the Great Roll of 

 the Pipe. 



" The Academy require no evidence to satisfy them, that 

 in historic importance the records of the country are the surest 

 and safest guides to the historian. No histories of Ireland, yet 

 published, synchronize with the records, but for the most part 

 are delusive and erroneous. 



" Nearly half of the last decade of the first moiety of a 

 century has passed since I commenced an investigation into 

 the ancient records of Ireland; and my accumulation of volumes 

 of manuscripts on the subject surprise even myself. Much was 

 done by the Record Commission, appointed in 1810, and the 

 ponderous volumes published by it demonstrate the value of the 

 muniments of the country, although they have not accom- 

 plished an object at all commensurate with the expenditure. 



" Little was done by that Commission to preserve them, or 

 make the records available. The subject has been brought 

 under the consideration of the Government of many adminis- 

 trations ; about four years since commissioners were appointed 

 to investigate the present state of the Irish records ; their 

 report has been made, and a bill was prepared to provide for 

 their safe custody, which has been long in the hands of the 



vol. v. L 



