404 Mr. Perigal on the Mode of Constructing the Pyramids. 



express p^ would be sufficient to exclude p from a claim upon 

 the exponent for its freneral logarithm. 



Mr. Graves says (Phil. Mag. S. 3. vol.viii. p. 281) "I call ^ 

 an e-log of— y/ e as well as of + Ve." But this departure from 

 the usual doctrine is not essential to the stability of Mr. Graves's 

 system ; and I submit that if, to subserve ulterior purposes, 

 + Ve be fixed upon, — Ve is at once deprived of its claim, 

 the ambiguity remaining only till the selection is made ; both 

 cannot claim this designation, but only one or the other, just 

 as in the case of + and — in the theory of coordinates. 



These few observations may perhaps contribute to revive 

 attention to Mr. Graves's interesting and masterly researches 

 into the general theory of exponentials ; and they may possibly 

 help to show that the system of imaginary logarithms which 

 he has established, is established upon precisely the same basis 

 as that which was required to support the older imperfect doc- 

 trine, without the aid of any new principle or postulate. 

 Belfast, November 12, 1844. 



LXX. On the Probable Mode of Constructing the Pyramids ; 

 introduced by Letters relating to the History of the subject, 

 addressed to Lieut.-Col. Sabine, Lieut.-Col. Dansey, and 

 the Author. By Henry Perigal, Esq.* 



To Lieut. -Colo7icl Sabine, F.R.S., ^-c, General Secretary of the 

 British Associatio?ifor the Advancement of Science, York. 

 Sir, 



IN offering for communication to the British Association 

 for the Advancement of Science the accompanying de- 

 scription of a (supposed Egyptian) mode of raising very large 

 stones, I take leave to annex copies of two letters, which ex- 

 plain that my discovery of this method of raising heavy weights 

 had been anticipated by Lieut.-Col. Dansey, of the Royal Ar- 

 tillery; and to add that, in an interview I sought with him, I 

 found that our plans were almost identical, and learned the 

 gratifying fact that in 1834, when the Egyptian antiquities at 

 the British Museum were transferred to the new gallery, under 

 the personal direction of Col. Dansey, this method was par- 

 tially adopted in the removal of "Young Memnon." Conse- 

 quently no doubt need be entertained of its he'\nfr practicable. 

 The question for discussion, therefore, is whether such a plan 

 was actually practised by the Egyptians in constructing the 

 Pyramids, &c. I am, Sir, yours truly. 



Smith Street, Chelsea, Sept. 24, 1844. Henry Perigal. 



• Coinmur.icated by the Author; having been read before the Section of 

 Mechanical Science of the British Association, at the (second) meeting 

 at York, September 27, 1844. 



