282 



Mr. W. H. Preece. 



[Dec. 22, 



Series I. " Cut-outs." 



Copper. 



Diameter of wire. 



Current in amperes. 



Fusing 

 current 

 calculated 

 from the 

 formula 

 ad*' 2 . 



Amperes. 



Constant 



"a" 

 when d 

 expressed 

 in inches. 



In 



inches. 



In 



centi- 

 metres. 



Standard 

 wire 

 gauge 

 No. 



Flake of 

 shellac 

 melted. 



Wire 

 red hot. 

 Visible 

 in air. 



Wire 

 fused. 



0-004 



o-oio 



42 



2 41 



3-057 



3 299 



3-48 



13033 



0-005 



0-013 



39 



2-896 



4-184 



4-586 



4-87 



12964 



0-007 



0-018 



37 



5-631 



7-000 



7-724 



8-07 



13183 



o-oio 



0-025 



33 



9-976 



14-160 



15-44 



14 23 



15433 



0-012 



0-030 



30 



11-22 



16 -29 



19-35 



18-71 



14748 



0-014 



036 



28 



13-68 



19-30 



21-84 



22 -86 



13162 



0-018 



-046 



26 



21 -71 



31 -43 



36 -40 



34-37 



15066 



0-020 



0-051 



25 



24 03 



35-61 



39 37 



39-05 



13699 



026 



0-066 



22 



30-69 



44 59 



54-43 



57-88 



12978 















Mean = 



13807 



