NEWTON'S REPEATED PROTESTATION that he was engaged in other studies supplied an ever-present theme to his correspondence of the 1670s. Already in July 1672, only six months after the Royal Society discovered him to be a man supremely skilled in optics, he wrote to Oldenburg that he doubted he would make further trials with telescopes, “being desirous to prosecute some other subjects.” Three-and-a-half years later, he put off the composition of a general treatise on colors because of unspecified obligations and some “business of my own wch at present almost take up my time & thoughts.” Apparently the other business was not mathematics, because later in 1676 he hoped the second letter for Leibniz would be the last. “For having other things in my head, it proves an unwelcome interruption to me to be at this time put upon considering these things.” He was not only preoccupied, he was almost frantic in his impatience. “Sr,” he concluded the letter, “I am in great hast, Yours. …” In great haste because of what? Surely not because of ten lectures on algebra that he purportedly delivered in 1676. And not because of pupils or collegial duties, for he had none of either. Only the pursuit of Truth could so drive Newton to distraction that he resented the interruption a letter offered. Newton was in a state of ecstasy again. If mathematics and optics had lost the capacity to dominate him, it was because other studies had supplanted them.