Advances in technology have transformed the nature of the human experience, and made possible previously unimaginable improvements in the quality of life. But technological advances can easily be harmful, even halting the course of social and economic progress. American slavery was a dying institution at the close of the eighteenth century, due to a combination of economic and moral factors. Free laborers feared economic competition from slaves; with their support, anti-slavery societies--aided by the spirit of the Enlightenment and the stirring (if sometimes muted) calls for equality of the American revolution--succeeded in abolishing slavery in the northern United States. At the time, many observers predicted the imminent demise of the slave system in the country as a whole. Then, at the close of the century, a simple invention changed everything. A young man named Eli Whitney developed the cotton gin.

Cotton had long had the potential to be a highly valuable crop. It was labor-intensive at nearly every stage of its development, making it most profitable for slaveholders, whose labor costs were only those needed to keep slaves alive. The difficulty lay in the fact that the process of separating the cotton fibers from seeds manually was so labor-intensive as to make the crop uncompetitive, even if slaves were doing the work.

Mr. Whitney's invention made the separation of cotton fibers from seeds a practical affair. Cotton was soon king, exceeding both tobacco and indigo in importance to the South. Vast new territories were opened up to cotton production, feeding the mills of England and the North. The South's infant industries were squelched, as all available capital and labor were poured into expanding cotton production. The rapid growth of cotton-producing areas induced a great demand for slaves, contributing to ever-more intense efforts to breed slaves in the manner of cattle, and to sell off family members with the same degree of consideration.

Thus did slavery perpetuate itself for seventy years, until war abruptly brought an end to the slave system. Upon meeting Harriet Beecher Stowe, whose Uncle Tom's Cabin had done so much to inflame northern opinion against slavery, Lincoln remarked, "So you're the little lady who started this great war." In truth, Eli Whitney's responsibility for the war was at least as great.

But the evil which technology had wrought was belatedly remedied by it in turn. The superior technical development of the North was decisive in determining the outcome of the war. The North's advanced industries churned out war supplies and materiel, from shoes to ships. Its more extensive railroad network allowed goods and armies to move rapidly within its territory.

Technologies may be used for good or for ill; a gun does not know whether its owner fights for freedom or for tyranny. Scientists, engineers, and inventors are in a unique position to influence the course of history. But they must do so cognizant of the impact their work has on society, and with a sense of responsibility commensurate with their power.