Graham's law has come to denote an important class of finely divided materials. Around the time Graham did his work, the concept of molecular weight was being established largely through the measurements of gases. Daniel Bernoulli suggested in 1738 in his book Hydrodynamica that heat increases in proportion to the velocity, and thus kinetic energy, of gas particles. Italian physicist Amedeo Avogadro also suggested in 1811 that equal volumes of different gases contain equal numbers of molecules. Thus, the relative molecular weights of two gases are equal to the ratio of weights of equal volumes of the gases. Avogadro's insight together with
History of same-sex marriage in the United States states to issue marriage licenses to same-sex couples and to recognize same-sex marriages validly performed in other jurisdictions. This held all state same-sex marriage bans to be unconstitutional and legalized same-sex marriage in all remaining states. The decision came on the second anniversary of the "United States v. Windsor" ruling that struck down Section 3 of the Defense of Marriage Act (DOMA), which denied federal recognition of same-sex marriages. It also came on the twelfth anniversary of "Lawrence v. Texas" which struck down sodomy laws in 13 states. Each justice's opinion on "Obergefell" was consistent with their opinion in "Windsor".