Quotation, "Who buys an American book?"

A British writer at the turn of the century (the 19th Century, of course, so call it 1810) asked "Who buys an American book?" He then listed many other "civilized" products not at the time produced in quantity by the former colonies -- and concluded with an excoriation of America's "peculiar institution", chattel slavery, which was still legal in parts on the US (and in smaller parts of the British Empire).

But I cannot find it in Google, except for some newspaper clipping that quote it as a famous saying! Does anyone have the original quotation, or even the name of the writer?

The original question appears to have been not "Who buys an American book, but "Who reads an American book?" The person credited with this quotation is the Rev. Sydney Smith, in the course of a wide-ranging review of Adam Seybert, Statistical Annals of the United States of America (1818), published in the January 1820 issue of The Edinburgh Review:

In the four quarters of the globe, who reads an American book? or goes to an American play? or looks at an American picture or statue? What does the world yet owe to American physicians or surgeons? What new substances have their chemists discovered? or what old ones have they analyzed? What new constellations have been discovered by the telescopes of Americans?—what have they done in the mathematics? Who drinks out of American glasses? or eats from American plates? or wears American coats or gowns? or sleeps in American blankets?—Finally, under which of the tyrannical old governments of Europe is every sixth man a Slave, whom his fellow-creatures may buy and sell and torture?

When these questions are fairly and favourably answered, their laudatory epithets may be allowed: But, till that can be done, we would seriously advise them to keep clear of superlatives.

In 1823, the best reply that a reviewer in the Niles Register (March 23, 1823) thought he could make was to point to The Pioneers, by James Fenimore Cooper, published that year:

THE PIONEERS. "Who reads an American book?" was the latest modest and liberal demand of the editors of the Edinburg Review. The "Pioneers," we venture to say, will be read by tens of thousands even in Great Britain. It does not appear to be second to the best production of the "great wizard of the north," as the author of the "Waverly novels" is called.

The variation "Who buys an American book?" arises in "Literature and Literary Progress in 1872," in The American Annual Cyclopedia and Register of Important Events, volume 12 (1873):

The question once asked, with more justice than our national susceptibility permitted us to see, "Who reads an American book?" now admits of no doubtful or hesitating answer. And, as we are every year becoming more characteristically a nation of readers, the question in a commercial version of it, "Who buys an American book?" need concern none but ourselves. But books that are worth buying for ourselves cannot fail to be in request abroad, and—whatever doubt may be raised as to some of the conclusions of political economy—nothing but good can come from the freest interchange of thought.