Part of the Wisconsin rebates were paid on State business, but far the larger part was on interstate traffic. The Elkins Law, instead of putting an end to the payment of rebates, as so many railroad men have declared, had no effect whatever, apparently, on the volume of rebates paid. Here is the monthly record of rebates paid in 1903 by one of the principal railroads operating in Wisconsin: January, 1903 $37,000 February 57,000 March 47,000 April 36,000 May 25,000 June 13,000 July 101,000 August 32,000 September 46,000 October 9,000 November 666 December 2,032 The Elkins Act went into effect February 19, 1903; yet the rebates in February and March were larger than in January; and the rebates for July were nearly three times the January figure. It is clear, however, that when the light of publicity was turned on by the investigation, which began September 29, 1903, the rebate payments that could be checked up on the books dropped from $46,000 in September to $9,000 in October, $666 in November, and $2,032 in December. Instead of paying cash rebates the railroads began to issue a great many “midnight tariffs,” that is, rate schedules printed on purpose to give favored shippers advantages over others and then revoked or superseded as soon as the purpose has been accomplished, so that the midnight tariff has, in a different way, done exactly what is done by the payment of the cash rebate. The impotency of the Elkins Law is still further shown by the fact that the total rebates paid by the railroads in 1903 were greater than the rebates of 1902. The Northwestern road, for example, jumped from $212,075 rebates in 1902, before the Elkins Law, to $410,476 in 1903, mostly after the Elkins Act took effect.