Zoological Summary of Extinct and Living Animals^ ^c, 353 



current seems to be the most powerful ; but this may be occasioned by 

 the predominance of heavy cloudy days during the present month. 



As the existence of electrical currents through the metalliferous veins 

 of the earth, has been demonstrated by Mr Fox, the details of these cases 

 of minute decomposition by feeble currents, may be useful to assist us 

 to comprehend the sources of change in the form and deposition of mat- 

 ter in the great laboratory of Nature. 



18. Since the experiments given in 14-16 prove the deposition of me- 

 tallic silver to be far within the range of thermo-electrical currents de- 

 rived from astral and solar influence, the question naturally arises, whe- 

 ther, in addition to the application of the battery, fig. 1, to meteorologi- 

 cal purposes, described (8.), it may be so arranged as to deposit silver, 

 through the calorific power of the summer's sun, and thus supply a scale 

 wherewith to measure or compare the solar heat of one season with that 

 of another. 



For our climate, to gain a range sufficiently great, currents derived 

 from several series of batteries must be passed into one voltameter, fig. 

 4, which, like the upper half of these batteries, must be exposed to sun 

 and sky. The experiment in 14. shews that the current in an opposite 

 direction can remove part of the silver deposited by day ; at temperatures 

 below G0°, I have always found the results of electrolysis so minute, for 

 currents derived from astral or solar influence, that this source of error 

 is imperceptible in the result; astral radiation acting on a battery, fig. 1, 

 for the three winter months, did not deposit silver to weigh ij^th of a 

 grain, yet with a magnifier the usual frosted appearance of the deposited 

 metal could be distinctly seen. In a warm climate, there can be little 

 doubt that the sun will deposit enough of metal for the required scale. 

 After the experience of 8 months with the action of this instrument in 

 our latitude, I believe that it will prove useful to those engaged with 

 inquiries into the extent of radiation in different climates. For example, 

 a battery, with its attached voltameter, might be placed in a high alpine 

 station, and left untouched for a year. 



[To be continued^ 



Zoological Summary of the Extinct and Living Animals of (he 

 Order Edentata. By Professor Owen. 



The light which is thrown on the nature of animals belong- 

 ing to extinct species by the comparison of their fossil remains 

 with recent skeletons, is very often reflected back, so as to 

 elucidate affinities of existing species which were before obscure, 

 and which must otherwise have remained subjects of debate 



