That's hard to say. Lewis, when he wrote, was a more engaging writer. He had a literary flare, and that's probably one reason Jefferson chose Lewis. Jefferson always thought of it as the Lewis expedition; it was Lewis who chose Clark. Clark's writing is more blunt, more matter-of-fact. His is shorter. His entries are more direct and to the point. Lewis can go on and on about something and sometimes that's very appealing. Other times you want to say 'get to the point.' When Clark's writing you beg for more so it's a sort of different way of writing. Lewis was a very inconsistent journalist. There are great gaps in his writing. The greatest was at the start. From May 14, 1804 to April 7, 1805, from the time they left to go up the Missouri from the time they left their winter encampment at North Dakota, Lewis made only sporadic entries, so we have Clark almost exclusively to deal with for our information about the expedition.