Labels:text | screenshot OCR: "Let smoke be made out of a small quantity of wood and let the solar rays percuss such smoke, and behind it place a piece of black velvet not to be reached by the sun. And you will see that all the smoke which comes between the eye and the darkness of the velvet will show itself of a very beautiful blue color; and if instead of the velvet you put a white cloth, the smoke will appear the color of ashes." (36r)
(.png)
.iso/data/e6.dxr/00196_Bitmap_12_05.3.pct/00196_Bitmap_12_05.3.png)