Manchester Memoirs, Vol. I. (1905), No. ^. 3 



The wire was heated electrically, and after a time a 

 number of striae made their appearance. 



The}' gradually broadened, and formed a series of 

 layers which were sharp at the top, and then faded away 

 until the next layer was reached (Fz£: 2). 



The effect is not quite so well marked as when the 

 liquid is heated directly, and so more uniformly by the 

 current. 



The sharpness and permanency of these boundaries 

 seems to indicate that there are vortex movements due to 

 convection currents between them. 



The pressure is greater at the walls, and the liquid 

 rises in the centre. Its place is taken by the cold liquid 

 from the outside, which rises in its turn, thus causing a 

 circular motion from the wire to the walls, between the 

 layers. 



The breadth of the bands appears to depend directly 

 on the difference of temperature of the inside and outside 

 of the liquid. 



Increasing the current sometimes even causes the 

 lines to become doubled, the original ones gradually being 

 effaced. 



If the tube is heated simultaneously from the inside 

 and outside by coiling another wire round the tube, the 

 layers do not appear ; there is, however, a tendency to 

 set up large convection currents, which rapidly mix the 

 liquids. 



As this is passing through the press, I notice an 

 abstract in Central Blatt, igo^, B II, No. 23 of a paper 

 by C. Christiansen, {Overs, o.d. Kgl. Dansk. Vidensk. 

 Selskab Fork, igos, 307-15,) who has obtained similar 

 results, and formed much the same conclusions as those 

 given above. 



