rrioTOMicROGR.iriiy .ixn rrxuNicAi. microscopy 129 



Moreover, it seems probable that the finest high-power objectives 

 are of a quahty be\ond our ability to use them to best advantage 

 lierausc of our incomplete knowledge of how best to prepare sf>ecimens 

 for examination at high powers. 



it is impressive to evaluate magnification in terms more readily 

 comprehended. For instance, the cross section of the average metal- 

 lurgical specimen ma\- be consideretl as a square whose side measures 

 one-half inch. If we magnify this specimen 100 times, obviously 

 we have an area measuring 50 inches on the side, but if we magnify 

 it 10,000 times, then we have the equiv'alent of an area about 415 

 feet on a side or roughly, about four acres. An average picture at 

 6,000 diameters is 6 inches in diameter and therefore by a reverse 

 order of reasoning, the actual area of the specimen under observation 

 iucomes 1, 1000 inch in diameter. 



