I.old [Brit əʊld, Am oʊld]RZ.The irregular form vieil of the adjective vieux/vieille is used before masculine nouns beginning with a vowel or a mute ‘h’.
I.people [Brit ˈpiːp(ə)l, Am ˈpipəl]RZ.(nation)gens is masculine plural and never countable (you CANNOT say ‘trois gens’). When used with gens, some adjectives such as vieux, bon, mauvais, petit, vilain placed before gens take the feminine form: les vieilles gens.
Gravity gradiometry is used by oil and mineral prospectors to measure the density of the subsurface, effectively the rate of change of rock properties.