Origin of Sdfaft'es ? — Ekcir'ical Doubler. 495 



Tfie number of tKefe figured bodies was about thirty-fix, though not all' of them equally 

 perfeft. And they evidently had been formed from a folid circular mafs of argillaceous iron- 

 ore, of about two feet and five inches in breadth, and four inches in tliicknefs, at the central 

 parts, and becoming thinner towards the edges. In the natural fra<flure of t}ie ftone, the 

 fragments took upon themfelves thefe regular forms, very much refembling bafaltes ; and, 

 like bafaltes, \hoi\^ figured they evidently are not cr^allizedy for they are as perfectly terri- 

 genous and opaque as any argillaceous- ore of iron whatfoevcr. 



I brought away fome of the pentagonal pieces, and could eafdy get more of them, for ia 

 taking out the few that I brought away, I difturbed the reft as little as poffible. 



Do not thefe fpecimens go very far towards deciding the difpute, if any doubts ftill re- 

 main, about the igneous or aqueous origin of bafaltes ? they fupport, by the moft powerful 

 evidence, the Neptunian origin of that kind of figured bodies, and are direftly oppofed to the- 

 Plutanic fyftem. The fpecimens before me prove, that argillaceous iron-ore, which nobody 

 has fuppofed to be a volcanic produftion, can take on a bafaltic figure. AVith Bergman, 

 Weideman, and Kirwan, I am inclined to believe the weight of teftimony is oppofed to the 

 formation of bafaltic columns by rusiON, and that the true manner, in which many, if not all, 

 of them have been produced, is in the moist way. This new proof, added to Mr. Kirwan's 

 very able paper on traps and bafaltes.^ I think fettles the controverfy in his favour. 



V. 



Conceraing the Invention of the Electrical Doabler. By Mr. JoHN READ. 



To Mr. NICHOLSON. 

 SIR, 



I 



N your journal, Nov.. 1 798, page 368, you charge me with want of candour, in my de- 

 fcription of what I call the fpedlacle doubler of eleftricity. Whether this charge be juft, or 

 not, muft be left to the decifion of a judicious public: who, it i* hoped, will have candour 

 enough to compare your account of the doubler with mine. I was of opinion, that after 

 giving you the priority of invention, which I have exprefsly done in page 29 of my work, 

 entitled Summary View of the fpontaneous Electricity of the Earth and Atmofphere, no 

 further acknowledgement could be required. The paflage is, " and to give the plates a con- 

 fiderably more extended infulation than that made by Mr. Nieholfon, without augmenting 

 the fize of the inftrument, Set." 



That your charge is frivolous, will more fully appear from the following circumftance, 

 namely, that Dr. Prieftley did aiftually deliver my original manufcript into your hands, with 

 full power to corredl, erafe, or add whatever you chofe, and after you had retained it more 

 than three months in your pofleflion, I received the manufcript from you, and found that you 

 had made no alteration at all in it: of courfe it went to tlie prefs in the drefs it is now in. 



It is not my intention, at prefent, to criticife on all you have faid in the paflage alluded to. 

 As to the adopting fome of your own words into my defcription, of nearly the fame inftrument, 

 could not well be avoided; nor can It be thought an illiberal proceeding. But if you difliked 



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