The power under the Unlawful Drilling Act 1819, of authorising meetings and assemblies of persons for the purpose of training and drilling themselves, or of being trained and drilled to the use of arms, or for the purpose of practising military exercises, manoeuvres, or evolutions, shall be exerciseable by a Secretary of State, or any officer deputed by him for the purpose, instead of by the lieutenant or two justices of the peace of a county.