Prout's hypothesis was an early 19th century attempt to explain the existence of the various chemical elements through a hypothesis regarding the internal structure of the atom. In 1815 and 1816, the English chemist William Prout published two papers in which he observed that the atomic weights that had been measured for the elements known at that time appeared to be whole multiples of the atomic weight of hydrogen. He then hypothesized that the hydrogen atom was the only truly fundamental object, which he called protyle, and that the atoms of other elements were actually groupings of various numbers of hydrogen atoms. Prout's hypothesis was an influence on Ernest Rutherford when he succeeded in "knocking" hydrogen nuclei out of nitrogen atoms with alpha particles in 1917, and thus concluded that perhaps the nuclei of all elements were made of such particles, which he named protons.

The discrepancy between Prout's hypothesis and the known variation of some atomic weights to values far from integral multiples of hydrogen, was explained between 1913 and 1932 by the discovery of isotopes and the neutron. Prout's hypothesis was then found to be correct for atomic masses of individual isotopes, to an accuracy not less than 99%.

Le Prout ou Prut (en roumain : Prut ou Prutul avec l’article postposé: « le Prut »; en ukrainien : Прут) ou Pruth (dans les livres anciens et les livres d’histoire), est une rivière d'Europe de l'Est et un affluent du Danube. Il est long de 953 km.

Gaz (گز) is the traditional name of Persian nougat originating from the city of Esfahan, located in the central plateau of Iran.

The name gaz is associated with gaz-angebin which translates to "sap of angebin"; in reference to a species of Tamarisk, T. gallica that is native to the Zagros mountain range located to the west of the city.

The sweet, milky sap (gaz of Khunsar) found on the angebin plant is associated with manna, a food mentioned in the religious texts of the Abrahamic religions. The sticky white substance, exuded from the anus of the last instar nymph of a small insect (Cyamophila astragalicola Gegechkori,Psyllidae or Cyamophila dicora Loginova) which lives on the plant, is collected annually and is combined with other ingredients including pistachio or almond kernels, rosewater and egg white. Modern versions of gaz may not contain gaz of Khunsar and may use sugar and corn syrup as substitutes. This combination of ingredients gives gaz its distinctive flavour, rendering it unique when compared to European nougats.

Once collected from the mountains, the gaz of Khunsar is brought into town and placed into very large copper vessels which contain the remaining ingredients of egg white, pistachio or almond kernels, and rose water. The raw mixture is then beaten over heat until it reaches the desired consistency.