Rafinesque, writing in 1830, in his _American Manual of the Grape Vines_, gives an account of forty-one species of native grapes. Unfortunately his "species" are founded upon the slightest differences in vine or fruit and his observations were so poorly made that his botanical studies of the grape are now wholly discredited by botanists. He gives an account of the acreage in vineyards existing in the United States in 1825 and 1830. This is the earliest estimate of the vineyard acreage of the country and is therefore a landmark in American viticulture. It is as follows:[71] "In 1825 I collected an account of our principal vineyards and nurseries of vines. They were then only 60 of 1 to 20 acres each, altogether 600 acres. While now, in 1830, they amount to 200 of 3 to 40 acres, or nearly 5000 acres of vineyards. Thus having increased tenfold within 5 years, at which rate they promise to become a permanent and increasing cultivation." Viticulture took its place in the literature of American pomology with the advent of William Robert Prince's _A Treatise on the Vine_. This work, magnificent compared with similar books of the time, introduces native grapes to the fruit-growers of America. Prince was the fourth proprietor of the same name of the Prince nurseries at Flushing, Long Island, and he with his predecessors had assiduously cultivated European varieties of grapes hoping to acclimatize them to American conditions. It is not a matter of wonder therefore, that much of his book is devoted to foreign grapes. His collection at Flushing consisted of over four hundred and fifty sorts and many of these he describes. In spite of his attraction to the foreign varieties, some of which had been tested in his nursery for two or three generations, Prince admitted the impossibility of growing them successfully and recommends to his readers and patrons the cultivation of native varieties. In the latter regard he says: "* * * after all my own experiments I have come to this conclusion, that to establish vineyards of the most profitable description, with a certainty of regular crops in localities north of the highlands in this state, _native varieties alone should be selected_; and the whole of the eastern states will of course be comprised in this remark."