ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
795 
from petty jealousy that marked liis character was pleasing to his many 
friends. No one ever heard him say a harsh word about rivals in trade, 
even when in the contests, called by some sharpness in trade, he might 
justly blame some for having acted unfairly. Those who have been for 
years in the habit of visiting him in his shop know how kind he always 
was and how patiently he listened to what they had got to say, giving 
freely from his great store of knowledge, showing his methods and even 
supplying to those who wished to make any piece of apparatus them- 
selves such parts as he could find suited to their purpose. 
Mr. Zentmayer’s office in Walnut Street, where he had his lathe 
close to his counter, and near to the cases containing his instruments, 
was the meeting place of all the scientists of the day. There at all 
times, while he was working, professors and physicians, and mechanical 
engineers, would meet and discuss problems in optics or in mechanism, 
all of these men learning to love the good man who was so simple- 
minded and so honest in his dealings. Many times young men coming 
to purchase their first Microscope, found the great optician advising the 
purchase of a good working instrument cheaper than the one they had 
come to buy, but well fitted to do what would be required of it. No 
instrument would leave his hands without being personally inspected 
by him, after he had advanced to the condition of employing workmen 
to do what at first he did with his own hands. All those who knew 
Mr. Zentmayer felt the influence of his honest, straightforward seeking 
after truth. It was always a source of pride to him that among the 
many thousand instruments which he constructed, none ever came back 
for repair after years of hard usage, except in the case of severe accident, 
such as would come from a fall or the like. No amount of work ever 
did them harm. 
The great triumph of his Microscope-making was the perfection of 
the stand, known as that of 1876, which elicited so much favourable 
comment during our Centennial Exhibition. The invention and 
practical application of his swinging substage, that enabled him to rotate 
the illuminating apparatus completely round the object without disturb- 
ing its focus, were marked examples of his talent. Others may claim to 
have made something similar, but none had ever made it so perfect as to 
be substantially new to all who used it. Now no good Microscope is 
made without this important arrangement of stand. The binocular 
Microscope, under his hands, became more useful than ever before. It 
was not until he had perfected this form that he was willing to sell a 
binocular instrument. He knew the good that was to be obtained by 
means of the binocular principle, but he was unwilling to make one for 
sale until at last he had surmounted all the objections he saw in the system, 
and had made so perfect an instrument that he did not fear to attach 
his name and reputation to it. 
In the construction of his simple form of sliding stage, others may 
claim the prior invention of the principle in a crude form, but it is very 
certain that to Mr. Zentmayer, and to him alone, is due the credit of 
making this simple device as perfect as the most costly compound stage, 
so far as comfort of working and certainty of motion are concerned. To 
suggest is one thing, but to perfect into an efficient instrument is 
perhaps the most important after all. 
1893. 3 I 
