Thirty-second Meeting of the British Association. 435 



iliat especial attention should be directed to this point on the next occur- 

 rence of a solar eclipse. The case in which the curvature of the path of 

 the raj' is greater than that of the globe was assumed to be that of the 

 sun's atmosphere ; and it was shown, on this supposition, that all objects 

 seen by ravs wLich come from the sun's periphery are brought by the 

 refraction to the level of the boundary of the atmosphere, whether they 

 proceeded from objects on the surface of the interior globe, or from clouds 

 supposed to be suspended in the atmosphere. Accordingly, the contour 

 of the sun should appear quite continuous, and the augmentation of ap- 

 paient semi-diameter will be equal to the angle subtended at the earth by 

 the whole height of the atmosphere. The apparent diameters of the 

 planets will, for like reasons, be augmented to a certain amount by the 



from the earth, the eclipse of a satellite will take place, as soon as the 

 visual ray is bent by the interposition of the atmosphere. 



Promsional Report on Thermo-electric Currents m Circuits of one 

 Metal; by Mr. F. Jenkin.— Mr. Jenkin first gave a short description of 

 the electrical currents to which he had drawn the attention of the Asso- 

 ciation at their previous meeting, as due to loose contacts between two 

 unequally heated wires of one metal. Experiments were then described 

 with loose contacts between wires of two dissimilar metals. The great 

 intensity of the currents so obtained, compared with the ordmary thermo- 

 electric currents from metallic contact between the two metals was pomted 

 out; and it was shown that an analysis of the results proved, beyond 

 doubt, that the currents were of the same nature as those produced by 

 unequally-heated metals placed in an electrolvte : the thm films of melted 

 oxyds of copper and iron constitute this electrolyte with unequally-heated 

 junctions at surface of the two wires. This theory requires that the oxyd 

 of copper should be considered far more positive ihan iron, and the 

 oxvd of iron far more negative than copper. Direct experiments with 

 oxyds of iron and copper between platinum wires confirmed this conclu- 

 sion. It wa^s however, still considered doubtful how far •^'^^[|'^^'y*^^^^|'|4 

 hLlJn'iL3,\ntTc"ipa\edTom'e'of' these results. A suggestion was ti.en 

 niade that the current observed by Magnus and others at the hret metallic 

 contact of unequally-heated wires of one metal may be due to the fact 

 that the electric'd qualities of a perfectly homogeneous metal do not 

 depend solely on its temper and temperature, as has ^^^f ^'l^^'^'' ^"P" 

 posed, but to some extent on Uie time during which it has been main- 

 tained at that temperature; a fact proved, as regards ff^rical resistance 

 bv Mr. Mathiessen. In support of this view, it was stated that the cur- 

 rents obtained from these metallic contacts are not instantaneous as gen- 

 erally supposed, but continue for, at least, five minutes alter contact as 

 been" made, gradually diminishing from a maximum to a zero. 



On the Zodiacal Light and Shooting Stars; by Prof. CHALUS.-The 

 phenomena of the zodiacal light, as gathered from observations made 

 both in northern and in southern latitudes, were stated to be as follows:— 

 As seen in north latitudes, it appears in the west after the departure of 

 twilight, as a very faint light, stretching along the ecliptic, about 10 

 Am. Jocb. Sci.-^eco>-d SEBa:9, Vol. XXXIV, No. m-Nov., 1862. 



