302 THE AMERICAN MONTHLY [Nov., 



placed j>8 close as possible to the staml. By ii little adjustment 

 the tlanu' jiave a field as hriulil and clearas an ordinary 1-5 inch 

 fielii. With a little focusing, ri'd blood was brought out dis- 

 tinctly. \N'iih a C eyepiece one white blood corpuscle filled 

 nearly the wiiole fifld. After this it was easy to get satislactory 

 illumination for tlu' 1-75, with a clear and llat field, with good 

 resolution and remarkable definition wlun the gnat aniplilica- 

 ' tion is considered. 



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

 t)rdinary microscopy. iSccond, in llcliomicrescopy. Third, in 

 microjthotography. 



HOW THIS OBJECTIVE tAMK TO HK MAUK IN BOi-TON, 



It was made, not as the yacht Vigilant, on j)urj)ose to beat u 

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

 the subjects of some 20 })apers which Dr. Harrinian had written 

 mainly on dentistry. Mr. Tolles had made ids first I-IG inch 

 objective for Dr. H. In 1870, he niade 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 i)roi)osition to make 

 a 1-75. Carte blanche was given as to time and price. 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 ahfcurance as to accom])li.-;hnient. When finished. Mr. 

 Tolles said he would never make another. None other has i)een 

 made. 



ESTIMATE OF THIS OBJECTIVE. 



After a use of the l-7b, 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 bo 

 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, Conrt., in September, 1827; 

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



