﻿44 Mr. A. S. Davis on the Probable 



The results achieved by the total prevention of the evolution 

 of hydrogen, by the author's process, are : — 



1st. The attainment of a perfectly solid coating with no pores. 



2nd. The ability to deposit to any thickness without any de- 

 terioration of coating, not only rendering the external protective 

 coating of varnish quite unnecessary, but making it easy to coat 

 a given article to any thickness without removing it from the 

 bath until it is finished. If desired, the coated article may be 

 pickled in brass-finisher's pickle, or it may be burnished, filed, 

 or otherwise treated as solid brass, to produce a serviceable 

 article. 



3rd. There being no evolution of hydrogen during deposition, 

 all the electric force is utilized in depositing metal, and no more 

 than one Wollaston's or Smee's cell is necessary to give a perfect 

 result. To save time in practice, it is often advisable to use a 

 single Bunsen's or Maynooth cell, or equivalent magneto-electric 

 power. 



4th. The solidity of the coating prevents the possibility of any 

 exudation or formation of spots, for there are no pores to occlude 

 the solution. 



Many square feet of cast and wrought iron have been coated, 

 and many varieties and different qualities of brass have been 

 produced, by the author's process. Amongst other work pub- 

 licly exhibited is a cast-iron roller weighing ninety-six pounds 

 and having a coating of twenty-nine pounds. 



The iron articles coated by the new process have all the 

 strength of iron and the beauty of brass, in consequence of the 

 complete command obtained thereby over the quality of the de- 

 posit, as well as its thickness and perfect structure. 



74 Brecknock Road, N. 

 December 1870. 



VIII. On the Probable Character of Cometary Orbits. By A. S. 

 Davis, B.A. } Mathematical Master, Leeds Grammar-School, 



[Continued from vol. xl. p. 190.] 



IN a previous paper on this subject I arrived at the conclusion 

 that out of every hundred comets approaching the sun in 

 hyperbolic orbits, and having perihelion distances greater than 

 the radius of the earth's orbit, more than twenty-three on the 

 average will have excentricities greater than 1*02. 



The assumptions on which this result was obtained were, first, 

 that the parallaxes of the stars nearest the sun are about half a 

 second; and secondly, that the velocities of comets at a great 

 distance from the sun vary from zero to three radii of the earth's 



