19th century in science Carnot captured some of the ideas of thermodynamics in his discussion of the efficiency of an idealized engine. Sadi Carnot's work provided a basis for the formulation of the first law of thermodynamics—a restatement of the law of conservation of energy—which was stated around 1850 by William Thomson, later known as Lord Kelvin, and Rudolf Clausius. Lord Kelvin, who had extended the concept of absolute zero from gases to all substances in 1848, drew upon the engineering theory of Lazare Carnot, Sadi Carnot, and Émile Clapeyron–as well as the experimentation of James Prescott Joule on the interchangeability of mechanical, chemical,
19th-century history of the Catholic Church in the United States used as a model for so-called "Blaine Amendments" incorporated into 34 state constitutions over the next three decades. These amendments prohibited the use of public funds to fund parochial schools and are still in effect today although a 2002 Supreme Court ruling partially vitiated these amendments. As of March 2009, no state school system had changed its laws to allow state funds to be used for this purpose. In the latter half of the 19th century, the first attempt at standardizing discipline in the American Church occurred with the convocation of the Plenary Councils of Baltimore. Two slaveholding states, Maryland