This consideration is also very strongly evident with regard to international trade. Here the division of labour is assisted by the difference in the products of different countries. There can be no doubt that the exchange of commodities between one nation and another tends to bring them together and to promote unity and harmony of interests. At the same time it is also likely to be fruitful in quarrels and bickering. We saw that Hiram was very much dissatisfied with the cities in Galilee which Solomon presented to him in the course of their semi-commercial transactions. He appears to have retaliated by making Solomon a very handsome present in gold; but Hiram seems to have been a very exceptional person, and it is probable that most traders who are dissatisfied with the consideration received would not have been so generous in expressing themselves. International commerce has also been a fruitful cause of disunion rather than unity when various nations have quarrelled with one another concerning the right to trade with a third people. If one nation is trading with another greatly to its profit, it feels that it has a grievance when it finds that a neighbouring nation is sending cargoes to the same destination and undercutting it and taking the cream of the trade. After religion, it is probable that trade has produced more bloodshed than any other form of human activity. At the same time there can be no doubt that on the whole its influence has been strongly on the side of unity and that it has done more to break down international barriers than any other influence that has operated in the course of history. The trader, as such, believes entirely and whole-heartedly in the unity of mankind. All that he wants to do is to buy his products as cheaply as he can and to sell them at the best possible price. Whether he buys at home or abroad, or whether he sells at home or abroad, is a matter of complete indifference to him except that, as has been shown, owing to variations in value in different parts of the world, he is probably likely to be able to make larger profits from foreign trade than in commerce at home. National preferences sometimes induce him to encourage home industry by buying home products when foreign goods would have paid him better, but in so far as this happens, he ceases to be a trader as such and becomes a mixture of trader and patriot. As buyers and sellers, however, mankind is, on the whole, singularly free from international prejudices. It was thought at one time that importation of foreign goods into England would be considerably checked by insisting upon marks of origin, that is to say, that imported goods should be stamped as such. This expectation, however, seems to have been entirely disappointed, since most buyers were not concerned with the question of the country whence the commodity that they bought came, and only considered whether it suited their purses and was what they wanted.