Manchester Memoirs, Vol. lix. (191 5), No. 1&. 43 



for the lecture course delivered in Edinburgh and in 

 Glasgow in the spring of 1807. 



Two of the sheets, numbered 34 and 35, represent 

 reacting quantities by formulae, almost in the manner of 

 a modern chemical equation. 



A minor point which has come to light in the course 

 of the study of Dalton's note-books in connection with 

 the diagrams, is a tri-dimensional formula for oxamide. 

 (Laboratory Note-book xi., p. 372, March, 1834.) Oxa- 

 mide was supposed to consist of one atom each of carbon, 

 hydrogen, oxygen and nitrogen, and these are figured in 

 the form of a tetrahedron, so that each atom is similarly 

 placed, in contact with the other three. 



Sheet 1. 



Plate III. 



" Elements." 



Several of the figures have been altered from those 

 originally inserted. Some of these alterations are visible 

 in the reproduction, the others can only be observed in 

 the original. Most of the figures have been enlarged 

 since they were first inserted The corrections detected are : 



Sulphur, from 12 to 13. 



Magnesia, originally 20, as shown in the plate, was 

 later covered with a slip of paper holding the figure 17. 

 At some later time the slip became detached, but the ink 

 stain from the superposed slip is plainly visible. 



Lime, from 23 to 24. 



Iron was originally 40, then altered to 38, and finally 

 covered with a slip of paper bearing the number 50. This 

 slip has been detached in order to disclose the figures 

 underneath, and is now shown in the reproduction along- 

 side the figures which it covered. 



Lead, from 95 to 90. 



