[3] From 1858 to 1865 he was chiefly employed in the public works department, either as acting or permanent secretary to the government of India, and from 1867 to 1871 he filled the post of director-general of irrigation, then specially created.

[4] During this period the entire administration of public works was reorganised to adapt it to the increasing magnitude of the interests with which this department had to deal since its establishment by Lord Dalhousie in 1854.

In 1878 he was appointed to act for six months as financial member of the governor-general's council, when he made proposals for meeting the difficulties arising from the depreciation of the rupee, then just beginning to be serious.

From that time he continued to take an active part in the efforts made to bring the currencies of India and England into harmony, until in 1892 he was appointed a member of Lord Herschell's committee, which arrived at conclusions in accordance with the views put forward by him in 1878.

He laid the foundations of the scientific study of Indian meteorology, organising a department whose labours have been of use in assisting to forecast droughts and consequent scarcity and of no little advantage to meteorologists generally.

A sound mathematician, Strachey delighted in mechanical inventions and especially in designing instruments to give graphic expression to formulas he had devised for working out meteorological problems.

In 1884 he designed an instrument called the 'sine curve developer' to show in a graphic form the results obtained by applying to hourly readings of barograms and thermograms his formula for the calculation of harmonic coefficients.