Many diagrams have been contrived for exhibiting colours under various references; the schemes of Kirclier, I,amon Newton, and Harris, are well known to these may be aded the devices and diagrams of Mr. Brockedon, Mr. Clover. Mr. Margraves, Goethe, Mr. Hayter, and Mr. Martin, to which have adverted in 4to 4to.edition of this work, p. 249. Adopting the doctrine of throe primaries. etc, the relations of colour; be illustrated by a great variety of trine figures; of which have in our " Chromatics" prefered the triaingle as the simple* and moat analagous for form and composition.