(51)expenditure on articles of special contingencies when the total item of charge exceeds Rs. 500, or in the case of mathematical or scientific instruments or models Rs. 1,500, or in the case of petty construction and repairs, Rs.'2,500 for anyone work;(G.O. no. 2271-E., dated the 9.4.1927 and para. 190, B. & O. Treasury Manual.)
