"...of the orthodox economists of that period, Jevons typifies the prevailing trend toward scientific correlation. His attempt to link the commercial cycle of prosperity and depression with the physical cycle of the solar spots forms perhaps the apex of..."
This is a reference to work Jevons did in the 1870s. I'd take some issue with Jevons's characterization here. There was nothing "typical" or "orthodox" about Jevons at this time, at least in Britain and America. What was more typical was Ricardo and Mill, and later Marshall's reworking of marginalism, as well as American institutionalists. But no matter - even if Peaslee mischaracterizes the 1870s, marginalism had made its mark by 1908 (or I suppose in this case 1913).
All this comes from the story The Shadow Out of Time. Not only is this a great one because its main character is an economist - it also has (probably unknowingly) a very economic theme: what Keynes called "the dark forces of time and ignorance that envelope our future". Peaslee is taken to another world by beings that can switch consciousnesses with other life-forms across time and space. These beings are not constrained by Keynes's "dark forces of time and ignorance," and so therefore probably live in a much different society than ours (perhaps one more consistent with Classical economics in that sense!). When Peaslee returns he has no idea what has happened to him, and he abandons economics and begins studying psychology - which of course is the direction that Keynes turned to when he realized the significance of these dark forces for the economy. Traditional economics could only get him so far - psychology, he realized, had to do a lot of work as well.