Electrical Discharge. 341 



and the imperfect construction of my instrument, viz. the 

 " thermo-electrometer*." 



3. As this is a question of much physical interest, moi'e especially 

 in the present progressive state of electricity as a science, and as 

 any observation of so skilful and profound a philosopher as M. 

 Riess merits great consideration, more especially when counte- 

 nanced by so distinguished a writer as M. De la Rive, I am 

 desirous to submit, for the consideration of those engaged in elec- 

 trical inquiries, some further remarks and experiments relative to 

 the exceptions thus taken to the accuracy of my early announce- 

 ments. I am led to take this step, being under the impression 

 that I may thereby benefit science, and throw some further 

 light on this interesting subject. I think it will be found that 

 M. Riess, on referring to my inquiries, has not clearly appre- 

 hended the phaenomena in question, so prominently set forth by 

 M. De la Rive. I may perhaps further claim, and not unrea- 

 sonably, the privilege of seeking to obtain some little justice for 

 myself, in reference to the remarks of M. Riess, viz. that my ex- 

 periments have proved " unfruitful," and that he has " shown the 

 falsity of my announcement," observations which seem to imply 

 a belief in the infallibility of his own deductions, and which he 

 thus erects into a sort of standard of value with which to com- 

 pare mine. I think, however, it will be found that the results 

 arrived at by ]\I. Riess, and quoted by M. De la Rive, are really 

 no others than those which I had myself previously obtained and 

 published in my memoir above mentioned (1) ; and I trust to be 

 enabled to satisfactorily explain in what consists the difference 

 in our interpretation of these results. 



4. Fu-st, however, I must beg to be allowed to submit a few 

 brief explanatory observations on the nature and construction of 

 my instrument — the thermo-electrometer, which M. Riess ima- 

 gines to have been so imperfect in my hands as to induce him 

 to place it under what he supposes to be a new form. The in- 

 strument has been much used, not only in this country but also 

 on the Continent, and has without doubt rendered good service 

 to the progress of electrical research ; it is, in fact, upon this 

 instrument that much of the real value of M. Riess's inquiries 

 depend. 



The lhermo-electrometer,PlateIII. figs. 1,3,3, was first invented 

 by me so long since as the year 1820, now more than thirty-five 

 years since, although M. De la Rive conceives he was the first 

 person who employed a contrivance of this kiudf. My original 

 instrument will be found in a quarto work, which I published in 

 1823, relative to the effectual protection of the British Navy from 



* Ann. de Chim. vol. Ixix. p. 1 13; and Traitede V Electricity, De la Rive, 

 vol. ii. p. 154. t Traite de I'Electricite, vol. i. p. 31. 



