Rcviexv of Iceoiews, l/i/lS. 



LEADING ARTICLES. 



i8i 



HOW AN OBELISK WAS RAISED. 

 The geared wheel and water buckets 

 worked by cattle embodies the principle 

 of the capstan, and Wilkinson and 

 most other Egyptologists suppose it to 

 have been introduced into Egypt at the 

 time of the Persian invasion B.C. 527, 

 but Its principle must have been used 

 as early as the time of the Papyrus 

 Anastasi I. By its use the obelisk was 

 hauled up and projected on top of a 

 sand-box. There must have been also 

 a solid wide border or ledge on each 

 side, and higher than the road bed, 

 not only for mounting the capstans, 

 but in order to be able to wedge the 

 obelisk back into position in case it 

 got out of line in coming up the in- 



would be cut off afterwards. The box 

 would be strongly buttressed to pre- 

 vent its bursting, and there would be 

 lashings about the pivoting point of tuc 

 obelisk. 



Fhe obelisk would at all times dur- 

 ing its pivoting be steadied by rope 

 guys from the head and heel, and the 

 pedestal would be placed at such a 

 point that the obelisk, when reaching 

 it, would rest on the edge of the heel 

 and there would be a space of five or 

 six inches at the opposite edge to clear 

 the sand out before bringing it to th' 

 vertical by means of the guvs. Very 

 likely the edge would be splintered on 

 account of the immense weight resting 

 on it, and it would necessarily pivot 



cline. The size of the box would be 

 at least 40 by 20 by 50, in order that 

 the obelisk might swing about its centre 

 of gravity. The box would be care- 

 fully caulked, and would contain ii,000 

 tons of sand, exclusive of the space 

 occupied b}' the pedestal, which weighs 

 461 tons. Haswell's Avierican Tables 

 give the weight of granite as 166 

 pounds per cubic foot and sand as 120 

 pounds per cubic foot. Perhaps Egyp- 

 tian sand and granite may be nearer 

 alike. The nearer they are the less 

 would be the tendency of the obelisk to 

 slide as it approached the perpendicular, 

 though any such small tendency could 

 be overcome by leaving at the quarry 

 a small projection on the obelisk nearl\- 

 under the centre of gravity, which 



on this edge when cdming to the ver- 

 tical. Probably it would jump an inch 

 or two just when it reached an upright 

 position ; but nearly all obelisks are 

 splintered at the base, and Professor 

 Borchardt's careful measurements show- 

 that the\- ne.irl)- all have jumped. 



THE FIGHT AGAINST TUBER- 

 CU EOS IS. 



Professor Metchnikoff, in the Januar\- 

 number of the Bedrock, discusses the 

 various methods which have been em- 

 ployed to fight against tuberculosis. He 

 deals only with pulmonary phthisis, 

 and treats shortly the history of the in- 

 vestigation of the disease ; showing that 

 it is contagious, but that the human 



