Effects of Mechanical Stress on Electrical Resistance. 283 



Maximum. Minimum. 



Length of humerus 0'19 0'17 



radius 0-215 O175 



metacarpus O19 0'16 



femur 0'215 0'21 



tibia 0-26 0'22 



metatarsus 0'203 0'18 



calcaneum CK)95 0'063 



astragalus (V04 0'035 



The small dimensions of all these Cervine remains suggest a com- 

 parison at first with the common Fallow Deer (Cervus dama) ; and it 

 is quite possible that some specimens ^notably those from Excavation 

 No. IV may represent this southern European form, which has 

 already been recognised by Busk in the caverns of Gibraltar. The 

 limb bones, however, appear to the present writer to be slightly more 

 robust than those of the Fallow Deer of corresponding size ; and the 

 antlers conclusively prove that most of the remains, at any rate, do 

 not belong to this species. The antlers may be assigned with 

 certainty to the small variety of Cervus elaphus which now lives in 

 Northern Africa, and is known as the Barbary Deer (Cervus ~barbarus 

 of Gray) ; the Maltese fossils, however, indicate an animal of smaller 

 dimensions than its existing representative and its contemporaneous 

 ally discovered in the caverns of Gibraltar. 



<; The Effects of Mechanical Stress on the Electrical Resist- 

 ance of Metals." By JAMES H. GRAY, M.A., B.Sc., and 

 JAMES B. HENDERSON, B.Sc., "1851 Exhibition" Science 

 Scholars, Glasgow University. Communicated by LORD 

 KELVIN, P.R.S. Received February 10, Read March 2, 

 1893. 



This investigation was begun under the instructions of Lord 

 Kelvin about a year ago, and has been continued since the beginning 

 of last year in conjunction with another on thermal conductivity, 

 for which a grant of 50 was made from the Government Research 

 Fund. 



The chief object of the investigation was to obtain quantitative 

 results of the variations of specific resistances of metals due to 

 stretching, twisting, drawing through holes in a steel plate, hammer- 

 ing, heating, and combinations of these, while in some of these cases 

 the alteration of density was also measured. 



The most exhaustive results that have been hitherto given in this 

 direction are those of Lord Kelvin, published in vol. 2 of his ' Re- 



