1871.] Notices of Books. 373 



soul of the dying Egyptian rested its hope of happiness in a 

 future state of existence was, that he had " not shortened the 

 cubit," whilst in that future state he expected to encounter as 

 one of his first sights " the God Thoth with the cubit in his 

 hand." Could one of the numerous mummies resting in the 

 museums on British soil now come to life again he would no 

 doubt recognise his god Thoth under the guise of the Astronomer- 

 Royal for the northern part of this island, who has so manfully 

 stood up for the accurate measurement of the old Egyptians' 

 monument of metrology, the Great Pyramid of Cheops. 



After all the time, trouble, and expense devoted by Professor 

 C. Piazzi Smyth to determining the minutest details of this 

 marvellous and mysterious monument of early engineering skill, 

 and his persevering efforts to read the riddle of its construction, 

 it must, to say the least of it, have been disappointing that when 

 the Lords of the Treasury had refused "to entertain the question 

 of the measurement of the Great Pyramid " suggested to them 

 in a formal report, the work should have been undertaken by 

 the Department of the Ordnance Survey as a parergon, a. bye- 

 work, a matter of secondary importance to the main object of 

 the expedition which was to survey the Sinaitic Peninsula, and 

 this without previous information to the man who had done most 

 to draw public attention to the desirability of this enquiry. 

 When, however, it appeared that the Director-General of the 

 Survey had published notes and opinions upon the Pyramid 

 itself, in which there was a considerable want of accuracy both 

 of calculation and of statement of lengths, it was scarcely to be 

 hoped that the results of the survey itself would be satisfactory 

 to those most anxious for it, since those results were not the 

 actual details of each individual measurement, but means arrived 

 at by calculations made by the department and not fully explained. 



Both Professor C. P. Smyth and Mr. Day devote a considerable 

 portion of their papers to the refutation of Sir Henry James's 

 calculations and deductions about the Pyramid, and as it seems 

 to us convict him of inaccuracy in his earlier remarks, and thus 

 throw a doubt over the results of the last survey. We hope this 

 may lead only to a fuller publication of all the data upon which 

 these results have been arrived at. 



The Report of Professor C. P. Smyth contains other interesting 

 matter, amongst which we would especially draw attention to 

 the determination of the causes of variation in the transit obser- 

 vations at the Carlton Hill Observatory. It was for some time 

 supposed that these originated in contractions and expansions 

 of the rock upon which the piers of the instrument rested ; but 

 on comparing the mean variations of the instrument for ten 

 years, with the mean variations of the temperature of the atmo- 

 sphere, and also of the earth at various depths, it appeared that 

 the extreme errors of the instrument preceded the supposed 

 cause. Experiment then showed that the piers themselves were 



