104 Proceedings of the Royal Irish Academy. 



a supposed piece of the true cross"; its under surface was fiat ; it rested upon 

 another crystal with four facets and a flattened point, fastened down by some 

 kind of plaster, in which were two small fragments of wood, one measuring 

 about five millimetres in length, the other being about the size of a pin's 

 head, and some dust. The smaller fragment crumbled into dust. Dr. G. H. 

 Pethybridge. M.E.I.A.. Professor H. H. Dixon, sc.D., F3.S., Professor II. J. 

 - jroour, B.SC, and Mr. A. C. Forbes, f.h.a.s., kindly examined the larger 

 piece under a microscope; its small size rendered any determination as to its 

 character doubtful, so Dr. Fethybridge undertook a further more searchiug 

 examination, and has kindly sent me the following note (with which 

 t Dixon concurred), giving the result: — 

 "The piece of wood, said to be a portion of the true Cross, is of light 

 nr, about live millimetres long, three-quarters of a millimetre wide, and one- 

 lift: Uimetre thick. It is most improbable that this piece of wood can 

 ha\' timber aa ordinarily understood. On the 

 other hand, microscopic examination of it both in cross-section and longi- 

 tudinal. . with certainty that it must have been derived 

 from a young twig or branch of a tree or shrub. Portion of the medullary 

 sheath of the t\\ b sent with prin 1 (protoxylem), and with some 

 half-dozen rows or s secondary wood. The secondary wood 



B only, having simple pits ; but it is 



qui' it had the specimen been larger, }'"iti"ii< of the secondary 



1, iucluii . In one part of the fragment 



small bordered pit was seen. From the small 



essarily - ich a mere fragment of wood the 



of the trv :b from which it was taken would be a 



matter S it difficulty, aDd one involving probably an inordinate 



amount of t : 



It is probable that the fragment represents the piece of the true Cross 

 whi i in the Life of St Mac Cairthinn 1 as one of the 



reli' shrine. It is Annals of Tigernach' 



ir ah 1123, that a piece of Christ's Cross was 

 bro- . »me of it was given to King Toirdelbach Hua 



who enshrined it at Roscommon : so a relic of the true Cross was 

 bro eland in the early part of the twelfth century. 



small crystal in the square setting on the rim was next removed ; 

 beneath it was some dust. 



> See the passage quoted by Dr. Lawlor in part ii of this paper, pott, p. llu. 

 5 iferu< Cdtiq'it. iviii. p. 43. tq. 



