162 



A paper by H. Deane, Esq., ' On a New Medium for Mounting 

 fresh or moist Animal and Vegetable Structures,' was. also read. 



After enumerating various disadvantages found in mounting objects, 

 both in the fluids hitherto employed and in Canada balsam, the author 

 went on to describe a substance which, in his opinion, would entirely 

 obviate the greater part, if not the whole, of these, and which also 

 appears to possess all the qualities required in a medium for mounting 

 objects in the modes referred to. It is composed of the following 

 ingredients: — Gelatine, 1 oz. ; water, 4 oz. ; honey, 4 oz. ; rectified 

 spirits of wine, ^ oz. ; kreosote, 6 drops. The gelatine is to be soaked 

 in water until soft ; the honey is to be raised to the boiling heat in 

 another vessel, and added to the moist gelatine ; the whole is then to 

 be made boiling hot; when it has somewhat cooled, but is still per- 

 fectly fluid, the kreosote and spirits of wine previously mixed together 

 are to be added ; the whole is to be filtered through fine flannel. 

 When cold the composition is in the form of a very stiff jelly, which 

 on being slightly warmed becomes perfectly fluid. He concluded 

 with some practical directions for its use, and also by an enumeration 

 of some of its advantages over former media for mounting objects. 



April 16, 1851. Dr. Arthur Farre, President, in the chair. 



Robert Semple Frere, Esq., Bransby Blake Cooper, Esq., and Wra. 

 R. Morris, Esq., were balloted for and duly elected members of the 

 Society. 



Dr. Asa Grav, Professor of Natural History in Harvard University, 

 Cambridge, Massachusetts, was balloted for and duly elected an ho- 

 norary member of the Society. 



A paper by W. Ladd, Esq., ' On an Improved Adjustment for a 

 Microscope,' was read. 



After pointing out the disadvantages of the ordinary rack and pinion 

 movement, Mr. Ladd described the improvement he had made, which 

 consists of the substitution of a steel chain, known as a " fusee chain," 

 for the rack, and a steel pin or axis for the pinion. The ends of the 

 chain are attached to the top and bottom of the sliding bar which 

 supports the body of the microscope, passing two or three times round 

 the steel pin or axis, which is furnished with a milled head. The mo- 

 tion thus produced is exceedingly smooth and even, and is not liable 

 to the disarrangement on account of wear, which forms the greatest 

 objection to the rack and pinion. A mici'oscope fitted up with this 

 movement was afterwards exhibited to the meeting. 



A paper by Messrs. Hassall and Coppin, being a description of 



