TY  - BOOK
AU  - ALLEN, H.S. 
TI  - A TEXT BOOK OF PRACTICAL PHYSICS
U1  - Pg60 
CY  - 1924
N1  - Pg mean Physics General & Mechanics Page 457-464 in A to Z Accession Register (Acc. No. Pg1-Pg228) & Page 640 (Acc. No. 224-231)
ER  -