CORRESPONDENCE. 
147 
words of Dr. W. B. Carpenter, “ i’s are often 4,” and in the words of 
Mr. F. H. Wenham, “ |’s are often | or yL, and sometimes ^1” 
Thus the makers may obtain a reputation for the performance of a 
low power to which they are not entitled. 
The Hunterian Museum and its Microscopical Collection, — In 
his annual report to the Council of the Eoyal College of Surgeons, 
Professor Flower, the Conservator, states that the additions to the 
Pathological Collection for the past year have been eighty-eight in 
number, as compared with sixty-two during the previous year, and 
that the microscopical characters of all recent specimens sent to the 
College and thought worthy of preservation have been carefully de- 
scribed and delineated by Mr. Goodhart, the Pathological Assistant, 
who, by the great zeal with which he has performed the duties 
entrusted to him, appears fully to deserve the eulogium of the 
Conservator. 
COEEESPONDENCE. 
[By a mistake of the printers, Mr. Tolies’ first letter was “ crushed out.” 
We now give it with his second one. — Ed. ‘ M. M. J.’] 
Angular Aperture of Immersion Objectives. 
To the Editor of the ‘ Monthly Microscopical Journal.' 
Boston, June 25 , 1872 . 
Sir, — I wish to announce that I have lately subjected high-angled 
objectives to the tank method proposed by Mr. Wenham for ascer- 
taining angular aperture, the objective being immersed (front surface 
dipped) in balsam. The result is very different from that which Mr. 
Wenham declared must happen. 
Let this note appear, if possible, in your August issue proximo, 
and I will describe my results and method particularly in ample time 
for appearance in your Monthly for September next. 
With my account I will send an objective , that my claimed results 
may he verified or disavowed. 
Very respectfully, 
Eobt. B. Tolles. 
To the Editor of the 1 Monthly Microscopical Journal .’ 
Dr. Henry Lawson, Boston, July 15, 1872. 
Sir, — In my note of June last, I declared my purpose to send 
an objective for test of angle in balsam. 
Professor Markoe, of this city, sails to-morrow, per steamer 
‘ Hecla,’ from this port ; and as an objective suitable to my purpose, 
made in 1869, has been very obligingly placed at my disposal by 
another gentleman of Boston, I venture to forward it to your care. 
