.30 mm .go /m 'j/o 



Fig. o. 



7U 3.W 3.90 1*50 510 510 630 



^' Etcher 



Scocle for £t/ier. 



^e for Methyl Alcoh(?l . 



(hrm 50 100 150 200 250 300 350 WO ^0 500 550 



Fig. 7. 



360 it20 hSO o'tO 600 660 



