136 SWAJIMERDAM'S CHIEF SECRET. 



very slow vertical motion, by which means the 

 operator could readily alter their height, as he 

 saw most convenient to his purpose. The office 

 of one of these arms was to hold the little 

 corpuscule, and that of the other to apply the 

 microscope. His microscopes were of various 

 sizes and curvatures his microscopical glasses 

 being of various diameters and focusses, and, 

 from the least to the greatest, the best that 

 could be procured in regard to the exactness of 

 the workmanship and the transparency of the 

 substance. 



His way was to begin his surveys with the 

 smallest magnifiers, and from thence to proceed by 

 degrees to the greatest ; and by nature and use he 

 was so incomparably dexterous in the management 

 of them, that he made every observation subser- 

 vient to the next, and all tend to confirm each 

 other and complete the description. But the con- 

 structing of very fine scissors, and giving them an 

 extreme sharpness, seems to have been his chief 

 secret. These he made use of to cut very minute 

 objects, because they dissected them equably, 

 whereas knives and lancets, let them be ever so 

 fine and sharp, are apt to injure delicate substances. 

 His knives, lancets, and styles, were so very fine, 

 that he could not see to sharp them without the 

 aid of the microscope ; but with them he could 



