VHI. MISCELLANEOUS. 235 



1092. Ingenhous' Apparatus for demonstrating the Con- 

 duction of Heat, with nine rods of different metals. 



Warmbrunri) Quilitz, and Co., Berlin. 



1093. Apparatus intended to produce the Curves of Ther- 

 mic Conductibility on the surface of bodies. 



On the glass support are placed plates coated with grease, which may be 

 coloured. The current of a battery is made to pass through the small platinum 

 ball, which is at the end of wires of the same metal, and which are put into 

 contact with the plate. 



1093b. Four Boxes, containing plates subjected to the action 

 of apparatus No. 1, and showing the isothermic curves produced 

 by the fusion of the grease upon 



A. Bluish schist, from the valley of Sulvan, near Vernagaz. 



B. Coal schist, from neighbourhood of Motivon, near the Col 



de Voza. 



C. Another schist from the Col de Voza. 



D. Septypite from Tholy (Vosges). 



E. Clayey schist. 



F. Hyaline quartz, with faces cut parallel with the axis. 



G. Trooshte, silicate of zinc, with faces cut parallel with the 



axis. 



H. Gneiss, fine grained, from the Val Anzasca, Monte Rosa. 



M. Jannetaz, Paris. 



VII. POLARIZATION. 



1095. Forbes* Mica Plates for the polarisation of heat by 

 refraction. University of Edinburgh. 



The mica is split into numerous thin films by careful application of heat, 

 and fixed in the wooden tubes at the proper polarising angle. 



VIII. MISCELLANEOUS. 



1096. Thermo-electric Diagram for teaching purposes. 

 (Trans. Roy. Soc. Edin,, 1872-3.) Professor Tait, Edinburgh. 



1097. Apparatus employed by Professors Stewart and 

 Tait for producing rapid Rotation in a Vacuum. 



Professor Steivart, Manchester. 



The driving shaft is of iron, and passes into the receiver through an iron 

 tube containing mercury, -which acts as a barometer. 



This instrument was constructed and in part'devised by E. Beckley, of the 

 Kew Observatory, or an experiment conducted by B. Stewart and P. G. Tait. 



