252 APPENDIX I. 



death, in 1908 to the Metallurgical Department of the- 

 University of Sheffield. 



(Prepared by Dr. H. C. Sorby, F.K.S., at 

 '' Broomfield/' Sheffield, 1863-5.) 



(2) The gold copper series of micro-sections prepared by 

 Professor J. O. Arnold, F.R.S. : — 



Pioneer sections made by Professor J. O. Arnold,. 

 F.R.S. , and Mr. Joseph Jefferson in 1893, showing 

 the. micrographic influence of small amounts of impuri- 

 ties on the structure of pure gold and copper, hence 

 the discovery of brittle intercrystalline cements. 



These were fully described in Engineering, 

 February 7th, 1896. 



(3) Framed signed portrait of the late Dr. H. C. Sorbv^- 



F.R.S. 



Professor Alexander Silverman (University of Pittsburgh). 

 — A new illuminator for opaque objects. (Exhibited by Mr. S. C,'. 

 Akehurst.) 



Dr. J. E. Stead, F.R.S. — An improved form of workshop 

 microscope designed by Dr. J. E. Stead and Messrs. J. Swift 

 and Son. 



Series of heat-tinted specimens, showing the structure of phos- 

 phor etic steels and metals. 



Dr. Marie Stores. — The microscope as applied to coal research. 

 Illustrated by thin sections of coal, showing differences in texture- 

 and of plant content. 



Mr. J. Strachan. — The use of the microscope in the examina- 

 tion of paper-making materials. 



(1) A series of slides showing various paper-making fibres. 



including both those in common use and a few unusual 

 fibres used during the war. 



(2) A series of slides showing dendritic growths of copper 



compound in paper, illustrating the application of the 

 microscope to the study of chemical changes taking 

 place in paper after its manufacture. 



Messrs. James Swift and Son, Ltd. — Microscopes for metal- 

 lurgy and mineralogy and apochromatic objectives. 



]\[essrs. Taylor, Taylor and TIgbson, Ltd. — 



A microscope for measuring the diameters of depressions made 

 when testing the hardness of metals by the Brinell method. 



The magnilication is 16 diameters. 



A graticule is incorporated enabling diameters up to about 

 7 mm. to be measured. 



The microscope stands on three feet, one of them beiug a 

 cloven foot, within the notch of which the object is easily centred 

 in the field of the microscope. The other two feet are adjustable up 

 and down bv means of a knurled nut. 



