"Much has been said by the historians of chemistry in praise of this theory as having served, in spite of its inaccuracy, to guide chemistry to great results, at a time when the science was not ripe for a juster theory. From this statement I must totally dissent. Its devisers assuredly were men of rare gifts, and their theory, welcomed by their fellows and immediate successors as a great boon to the science, exerted for some forty or fifty years a strange fascination over all the chemists of Europe. These forty years, however, were like those spent by the Israelites in the wilderness, after their glimpse of the Promised Land."