LECTURE ON SUNDIALS

Evening Post, Volume CXV, Issue 104, 5 May 1933, Page 13

LECTURE ON SUNDIALS

Even in this age. of clocks and radiobroadcasting, a "sundial was not a mere toy or artistic adjunct to &■ country garden, b-ai could be.of considerable practical' utility, remarked Professor D. M. Y. Soaimerville in the course, of a paper read to the Astronomical Section, of the Wellington Philosophical Society ■on "Wednesday. In an interesting address/ he traced the early history of sundials from the Chaldaeans through the Greeks and Arabians to the seventeenth century, when a great deal was written about them and much mii genuity displayed in - their construction. The general principles of the ordinary sundial or gnomon were explained, and it was shown haw a dial of this type, which has been constructed for a.particular latitude, can be set up and used correctly in any1 other latitude. Thus a h6rizontal dial constructed for the latitude of London will be correct for Wellington when the dialplate is inclined downwards from the prime vertical at an angle of about 2% degrees. The lecturer described in detail ,two sundials: the first a; portable carddial dating from the fifteenth, century, interesting on account of the ingenuity of its principles; the second a modern type of instrument, as designed by Professor Cooke, of Sydney, which automatically applies the necessary corrections for equation of time and longitude, and .is capable of giving the time eorvectly to .within .a minute t or two.