PHILOSOPHICAL SOCIETY OF WASHINGTON. 35 



The laws restrict their investments to the best classes of securities. If 

 there is any class oppressed by the want of loans it is poor people^ 

 They have a little money or negotiable property laid aside, upon 

 •which they frequently want to borrow, but they find nobody willing 

 to loan upon it. Their only resource is to go to the note shavers 

 and curbstone brokers, who charge them an exorbitant interest. 

 Their wants, in his opinion, could be met by the savings banks. 



Mr. J. J. Woodward read a communication entitled 



EIDDELL'S BINOCULAR MICROSCOPES. — AN HISTORICAL NOTICE, 



which is printed in full in the American Monthly Microscopical 

 Journal for December, 1880. 



[Abstract.] 



Mr. Woodward exhibited a large binocular microscope, which 

 he stated had been made for the late Dr. J. L. Riddell, then Pro- 

 fessor of Chemistry in the University of Louisiana, during the 

 winter of 1853-4 by the Grunow Brothers, of New Haven, Con- 

 necticut, and presented to the Army Medical Museum in April, 

 1879, by Dr. Riddell's widow. 



He said that, although the proper merit of Riddell as a discoverer 

 in this connection had been duly acknowledged by such high con- 

 tinental authorities as Hartiug and Frey, and even by some English 

 writers, it had been strangely ignored by others, and that even so 

 fair and usually so accurate an author as Dr. Wm. B. Carpenter 

 had fallen into the error of asserting that " the first really satisfactory 

 solution of the problem was that worked out by M. Nachet ;" an 

 error the more remarkable in view of the manner in which Riddell's 

 discovery was published and discussed in England, and of the 

 manner in which it had been used by the opticians of that country. 



Mr. Woodward then offered evidence to show that Riddell was 

 the first to discover and publish the optical principle on which all 

 the really satisfactory binocular microscopes made prior to the pres- 

 ent year depend, as well as the inventor of two efficient and still 

 much employed methods of applying that principle ; one suitable 

 for the simple or dissecting microscope, the other for the compound 

 microscope. 



Riddell's discovery was, briefly, that the cone of rays proceeding 

 from a single objective may be so divided by means of reflecting 

 prisms, placed as close behind the posterior combination of theob- 



