On the Mean DejisHy of the Earth. lis 



matters would be rapidly disengaged, the surface would be 

 broken, air would act upon tlie metals, inflammation would 

 take place, and the result would be lava, the niclals of the 

 earths combined with oxygen." 



NoWjMr.T., will it not be understood bv every rcaderof 

 this paragraph, who may not have been otherwise informed , 

 on these matters, that Mr. C. and Dr. M. have been the 

 only, or the first, or the priticipal determiners of the mean 

 density of the whole earth, and the auth:)rn of the idea of 

 immense quantities of metallic n\atter about the central 

 parts of it? I cannot suppose that the paragraph has been 

 so worded by sujijircssine: his name, purposely, to throw the 

 slightest disparagement on the labours of the person who 

 first and chieflv computed that density, and suggested in 

 consequence that idea of the metallic iiilerior parts : yet, 

 it seems strange that the name of Dr. Hulton s'lould be 

 omitted in the mention of a circumstance in which he was 

 the chief efficacious person, especially when other names, 

 of inferior concernment in the business, are so pointedlv 

 announced. I trust, therefore, that Mr. T. will have the 

 goodness to allow me the favour of doing nivstlf barely 

 justice, in thus publicly slaline the claim to which mv la- 

 bours have entitled me, as will appear in the followuig short 

 hist iry of this business. 



About the year 17 74, there was much conversation 

 among some of the most scientific members of the Royal 

 Society, about the universal attraction of all matter, and in 

 devising some general and fan)iliar proofs of it. It was 

 then concluded that it Vv'ould he a very decisive, and, in- 

 deed, palpable proof, if it could be exptiinientally shown 

 that any hill attracted a plummet, drawing it sensibly aside 

 from the perpendicular direction, towards itself. In pur- 

 suing this idea, it was soon perceived, that as anv hill, es- 

 pecially in this country, is verv small in comparison with 

 the whole earth, the etiect of its attraction, in draAJna; the 

 plummet aside, must be extremely small, probably but a 

 very few seconds of a degree. Besides the nvuinitude of 

 a hill, it was considered that the effect would be increased 

 bv the circumstances of its shape; such as, that it should 

 be of a form very long and narrow, the sides very steep 

 and lofty ; on all which accounts it might be expected to 

 produce the greater efiect on the plummet placed near the 

 middle of a side of the mountain. The trial having been 

 resolved on, several persons were directed to search through 

 the island, and to make inquiries for hills having jiruperties. 

 nearest approachiiiix to those above mentioned. After se- 

 Vol. 3S. No. iCO. Au^riiit 1811. H veral 



