The book “the theory of perspective demonstrated; in a method entirely new by which the several planes, lines and points, made use of in this art, are shewn in the true position in which they are to be considered” by John Lodge Cowley (1719-1797), published 1765 in London can be found in the ETH-Bibliothek RA Rara Rar 3680 or online: https://www.e-rara.ch/zut/content/titleinfo/5909224
#20-937-082 #Cowley