Side-lights on astronomy and kindred fields of popular science; essays and addresses (1906)
Newcomb, Simon, 1835-1909 · New York Harper · leaf 101
spond-ing form. It is impossible to make a tool perfectlyspherical in the first place, but success may be se-cured on the geometrical principle that two surfaces 81 SIDE-LIGHTS ON ASTRONOMY cannot fit each other in all positions unless both areperfectly spherical. The tool of the optician is avery… … THE OPTICIAN S TOOL covered on the interior with a coating of pitch froman eighth to a quarter of an inch thick. This ma-terial is admirably adapted to the purpose because itgives way certainly, though very slowly, to the press-ure of the glass. In order that it may have room tochange its form,…
Astronomy
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Divina proportione : opera a tutti glingegni perspicaci e curiosi necessaria oue ciascun studioso di philosophia: prospettiua pictura sculptura: architectura: musica: e altre mathematice: suavissima: sotile: e admirabile doctrina consequira: e delecterassi: co[n] varie questione de secretissima scientia (1509)](https://img.insideoutlibrary.com/img/200/ia-divinaproportion00paci-266-446.webp)
![An illustration from Famous airmen and their equipment [electronic resource] : with some notes on first-aid in emergencies (1912)](https://img.insideoutlibrary.com/img/200/ia-b20457716-17-13.webp)
