Account of a tract by J Weidler on the parhelia (mock suns) witnessed at Wittemberg Account drawn up by Thomas Stack Tract divided into 17 sections Parhelia witnessed in January 1736 Greater detail given about sections 15-17 15th section - Weidler refutes Huygens' method of accounting the halo 16th section - Weidler gives his views about parhelia 17th section - explains the appearance of an inverted iris Appendix - account of the red lights seen on 5 December 1737 Read to the Royal Society on 22 March 1738 1738