The remedy for these evils is to be found in specific duties, so far as this may be practicable. They dispense with any inquiry at the custom-house into the actual cost or value of the article, and it pays the precise amount of duty previously fixed by law. They present no temptations to the appraisers of foreign goods, who receive but small salaries, and might by undervaluation in a few cases render themselves independent. Besides, specific duties best conform to the requisition in the Constitution that "no preference shall be given by any regulation of commerce or revenue to the ports of one State over those of another." Under our ad valorem system such preferences are to some extent inevitable, and complaints have often been made that the spirit of this provision has been violated by a lower appraisement of the same articles at one port than at another. An impression strangely enough prevails to some extent that specific duties are necessarily protective duties. Nothing can be more fallacious. Great Britain glories in free trade, and yet her whole revenue from imports is at the present moment collected under a system of specific duties. It is a striking fact in this connection that in the commercial treaty of January 23, 1860, between France and England one of the articles provides that the ad valorem duties which it imposes shall be converted into specific duties within six months from its date, and these are to be ascertained by making an average of the prices for six months previous to that time. The reverse of the propositions would be nearer to the truth, because a much larger amount of revenue would be collected by merely converting the ad valorem duties of a tariff into equivalent specific duties. To this extent the revenue would be increased, and in the same proportion the specific duty might be diminished. Specific duties would secure to the American manufacturer the incidental protection to which he is fairly entitled under a revenue tariff, and to this surely no person would object. The framers of the existing tariff have gone further, and in a liberal spirit have discriminated in favor of large and useful branches of our manufactures, not by raising the rate of duty upon the importation of similar articles from abroad, but, what is the same in effect, by admitting articles free of duty which enter into the composition of their fabrics.