1873.] Lieut.-Col. A. R. Clarke on Standards of Length. 407 



(suprastapedial), and the part loosely attached to the mandibular arch 

 is the elongated extrastapedial. The short stylo-hyal afterwards 

 coalesces with the body of the upper .or incudal segment by an after- 

 growth of cartilage (the interhyal tract) ; a long membranous space 

 intervenes between it and the glossal piece (cerato-hyal.) Thus the 

 " columella " of the Bird is formed of one periotic and three hyoidean 

 segments. 



In the Pig, the hyoidean arch is distinct, but articulates closely with the 

 mandibular ; its upper segment (hyo-mandibular) is converted into the 

 incus, and becomes connected with the stapes. The stylo-hyal is dislocated 

 and coalesces with the opisthotic region of the auditory capsule. 



XIV. " Results of the Comparisons of the Standards of Length of 

 England, Austria, Spain, United States, Cape of Good Hope, 

 and of a second Russian Standard, made at the Ordnance 

 Survey Office, Southampton." By Lieutenant-Colonel A. R. 

 Clarke, C.B., R.E., F.R.S., &c,, under the direction of 

 Major-General Sir Henry James, R.E., F.R.S., &c., Director- 

 G-eneral of the Ordnance Survey. With a Preface and Notes 

 on the Greek and Egyptian Measures of Length by Sir 

 Henry James. Received May 21, 1873. 



(Abstract.) 



The following account of the results of the Comparisons of the 

 Standards of Length of England, Austria, Spain, United States, Cape of 

 Good Hope, and of a second Russian Standard at the Ordnance Survey 

 Office has been drawn up by Lieutenant-Colonel Clarke, and is a sequel 

 to the abstract of the results of the Comparisons of the Standards of 

 Length of England, Prance, Belgium, Prussia, Russia, India, and 

 Australia which the Royal Society has done us the honour to publish 

 in the Philosophical Transactions for 1867, vol. clvii. p. 161. 



The accurate determination of the lengths of the various standards 

 employed by so many nations in the measure of the bases of their 

 triangulations, which are now being united into one vast network of 

 triangles, covering the whole of Europe, can scarcely fail to be of great 

 importance for the advancement of physical science. To the comparison 

 of these lengths I have added the result of our endeavours to recover 

 the correct lengths of the most ancient measures of length with which 

 we are acquainted, viz. those of Ancient Egypt, not only because our 

 own measures are obviously derived from them, but also because we 

 thus obtain the accurate relative value of the measures and distances 

 given in the most ancient works on Astronomy and Geodesy which have 

 come down to us. 



The Ancient Egyptians employed two measures of length, viz. the 

 common and the royal cubits. 



2k2 



