PLATES. 



I. & II. Illustrative of Prof. Silas W. Holman's Paper on the Effect of 

 Temperature on the Viscosity of Air and Carbon Dioxide. 



III. Illustrative of Mr. C. V. Boys's Paper on a Machine for Solving 



Equations. 



IV. Illustrative of Prof. S. P. Langley's Paper on Invisible Heat-Spectra 



and the Recognition of hitherto Unmeasured Wave-lengths. 



V. Illustrative of Mr. W. Baily's Paper on a Map of the World on 



Flamsteed's Projection. 



VI. Illustrative of Prof. Silvanus P. Thompson's Paper on some New 

 Polarizing Prisms. 



