302 THE AMERICAN MONTHLY [Nov., 



placed as close as possible to the stand. By a little adjustment 

 the flame gave a field as bright and clear as an ordinary 1-5 inch 

 field. With a little focusing, red blood was brought out dis- 

 tinctly. With a C eyepiece one white blood corpuscle filled 

 nearly the whole field. After this it was easy to get satisfactory 

 illumination for the 1-75, with a clear and flat field, with good 

 resolution and remarkable definition when the great amplifica- 

 tion is considered. 



The objective has done good work in three ways. First, in 

 ordinary microscopy. Second, in Heliomicroscopy. Third, in 

 microphotography. 



HOW THIS OBJECTIVE CAME TO BE MADE IN BObTON. 



It was made, not as the yacht Vigilant, on purpose to beat a 

 foreign one, and uphold national honor, but to help work up 

 the subjects of some 20 papers which Dr. Harriman had written 

 mainly on dentistry. Mr. Tolles had made his first 1-16 inch 

 objective for Dr. H. In 1870, he made his first 1-50 also for Dr. 

 H. Being so well satisfied with these objectives, Dr. H. was 

 desirous to go to the utmost stretch of human abilities in the 

 prosecution of his demonstrations, and the verification of his re- 

 searches. He approached Mr. Tolles with a proposition to make 

 a 1-75. Carte blanche was given as to time and i^rice. It was 

 a new idea. At first Mr. Tolles would not entertain it. By per- 

 sistence he was induced to undertake but without giving any 

 positive assurance as to accomplishment. When finished, Mr. 

 Tolles said he would never make another. None other has been 

 made. 



ESTIMATE OF THIS OBJECTIVE. 



After a use of the 1-75, and a wide demonstration of its work 

 for nearly twenty years, the writer thinks that it has brought 

 out details and features of suitable objects better than lower 

 powers have brought them out. Good judges in this and in 

 other lands have agreed with this estimate, so that it can be 

 said that this instrument of precision is a unique and justly 

 famed masterpiece, that confers honor on American talent and 

 executive abilities. 



WHO WAS ROBERT B. TOLLES ? 



He was born in West Winstead, Conn., in September, 1827; 

 moved to Boston in 1857, where he died in 1883. Early in life, 



