Well, i'm playing as the USA at the minute and it's 1874 i think. I have plenty of European pop's coming into California and there are empty factories waiting for them. The only problem is that they arrive with never more than 500 per pop and leave a maximum of a week later, even when they're working in a factory. I have the Socialists in power, all the right reforms but not one of the immigrants will ever stay, is this a bug or am i doing something wrong?