26 John Grattan : 



on the Round Towers of Ulster. At Getty's request Grattan 

 agreed to describe these skulls, but like the most of us he found 

 it easier to promise than to perform. As we have just heard, 

 Grattan was convinced that the various methods of measuring 

 skulls then in vogue were too indefinite and incomplete to admit 

 of a thorough and scientific description of individual specimens, 

 or of a comparison of groups of skulls with one another. 

 Accordingly he set to work to frame a new plan of skull measure- 

 ments, and in so doing he found it necessary to construct a 

 suitable instrument with which to take these measurements. For 

 a number of years Grattan worked at this subject, modifying his 

 methods and improving his instrument, until they were not only 

 greatly in advance of those then in use, but in many respects will 

 bear favourable comparison with those now generally employed. 



Through the kindness of Professor Haddon I am able to show 

 you what I believe was the latest and most improved form of 

 Grattan's Craniometer. No account of this instrument has been 

 published, although Grattan prepared a fine illustration and wrote 

 an excellent description of it for a paper which was not completed 

 at his death. He appears to have used this instrument in the 

 preparation of his " Notes on the Round Towers of Ulster, with 

 some additional observations towards a Crania Hibernica," which 

 appeared in the Ulster Journal of Archeology in 1858, and it was 

 probably shown before the Society on the 20th of January of the 

 same year. An instrument constructed on much the same principle 

 as the one before you, but differing considerably from it in ap- 

 pearance, was described and figured in the Ulster Journal of 

 Archeology for 1853. 



I will now endeavour to explain,. in a manner as simple and as 

 free from technicalities as possible, the problem with which 

 Grattan had to deal and the main peculiarities of his methods and 

 instrument. 



As the cranium is an irregular ovoid box we can obtain data 

 for a rough estimate of its size and general form by measuring its 

 greatest length, breadth and height. Further, by taking its length 

 as 1 00 we can express the proportions of length to breadth and of 



