A. MATHEMATICS AND ASTRONOMY. 5 



used the clippings of the stones for this purpose. From the 

 dimensions and position of the Queen's Chamber, Professor 

 Smith concludes that the builders employed the star Alpha 

 Draeonis, and Eta Tauri, the brightest star of the Pleiades, 

 as the starting-point in their astronomical measurements, 

 and that the time of building must have been about the year 

 2100 B.C. This latter date, however, depends entirely upon 

 modern astronomical measurements, which, it must be remem- 

 bered, do not afford so secure a basis for a retrospective cal- 

 culation of this nature as is necessary to an accurate deter- 

 mination of the very century in which the Pyramid was built. 

 In certain relations between the dimensions of portions of the 

 Queen's Chamber, Professor Smith finds evidence that the 

 builders were acquainted with what is known as the ratio of 

 the circumference to the diameter of a circle to within the 

 one-millionth part of its value. 4 Z>, 1873, II., 330. 



TESTING WEIGHTS IX ENGLAND. 



According to The Academy, a balance has been placed at 

 the entrance gate of the Royal Observatory at Greenwich, 

 which shows, by means of an index on a large divided arc, 

 how many grains too light or heavy any ordinary pound 

 weight may be. Any one, therefore, has it in his power to 

 test his weights, and to determine whether they are accurate 

 or not. 13 A, February 7, 1874, 151. 



MORPHOLOGY IN ARCHITECTURE. 



At one of the recent sittings of the Academy of Fine Arts 

 in Paris, M. Hugo, member of the Mathematical Society 

 founded at Paris since the war, presented to the Section of 

 Architecture a morphological theory, which he considers as 

 fundamental. This theory undertakes, according to him, to 

 show mathematically the connection between the polygonal 

 figures which are so frequently employed in monumental 

 constructions. These figures are derived from the pyramid, 

 and, according as the solids in question are more or less mass- 

 ive than the pyramid, they are divided into domoids and 

 tremoids. If we increase the number of faces, we arrive at 

 the solid of revolution just as w r e pass from the prism to the 

 cylinder. The new and very remarkable figure which gen- 

 erates the sphere has received the name of equi-domoid. 



