There is only so much you can learn about Russia's lakes from a set of playing cards. That said, they do include nuggets of information here and there. We learn, for example, that Novgorod Province has 3,220 lakes, and Lifliand has 1,000.
By contrast, the Geographical Atlas of the Russian Empire maps 5,637 lakes (and inland seas) with a total area of 253,258 square kilometers. The largest is Lake Baikal. The calculated area given here is 33,563 square kilometers; modern science puts the lake's area at 31,722 square kilometers (9.5% smaller than Piadyshev's atlas would have us believe). Lakes Ladoga and Balkhash come next in terms of size. By contrast, 5,416 have an area less than 100 square kilometer and 823 have an area of less than 1 square kilometer. The mean area is 44.9 square kilometers.