To support the statement that in the late 1800s a law made it easier for magazine companies to do business, the best evidence would be the introduction of the Postal Act of 1879. This law significantly reduced postal rates for periodicals, allowing magazines to be mailed more affordably and efficiently. By lowering costs associated with distribution, the act enabled magazine companies to reach a broader audience, thereby facilitating their growth and sustainability in the market.
If available, you might also look for statistics showing the increase in the number of magazine publications or circulation figures after the implementation of this Postal Act, as these would further illustrate the impact of the law on the magazine industry during that period.