1 March 1864. Baird was employed as special assistant engineer of the Bombay harbour defence works, and had charge of the construction of the batteries at Oyster Rock and Middle Ground until the end of 1865. He was then appointed special assistant engineer in the government
reclamations of the harbour foreshore. During 1868 he served as assistant field engineer in the Abyssinian expedition under Sir Robert Napier, afterwards Lord Napier of Magdala [q. v.]. For his work as traffic manager of the railway from the base he was mentioned in despatches (Lond. Gaz. 30 June 1868), and received the war medal.
In December 1869 Baird became assistant superintendent of the great trigonometrical survey of India. He was employed successively on the triangulation in Kathiawar and Gujarat. His health suffered from the extreme heat in this arid country, and he went on furlough to England in the spring of 1870. While he was at home, Colonel (afterwards General) James Thomas Walker [q. v.], the surveyor-general of India, chose him to study the practical details of tidal observations and their reduction by harmonic analysis as carried on under the supervision of Sir William Thomson, afterwards Lord Kelvin [q. v. Suppl. II], for the British Association.
Tidal observations were only undertaken by the survey of India, in the first instance, with the object of determining the mean sea level as a datum for the trigonometrical survey. But Baird, widening his aim, determined ' to investigate the relations between the levels of land and sea on the coasts of the gulf of Cutch, which were believed by geologists to be gradually changing. This necessitated a more exact determination of the mean sea level than had hitherto sufficed for the operations of the survey' (Baird, Manual of Tidal Observations, and their Reduction by the Method of Harmonic Analysis, 1886, pref.). It was decided to carry out observations at stations in the gulf of Cutch, in accordance with the recommendations of the tidal committee of the British Association, by self-registering gauges, set up for at least a year at a time. Having returned to India in December 1872, Baird selected three stations on the gulf of Cutch for his tidal observatories, one at the mouth, another at the head and as far into the 'Runn' as possible, and the third about the middle of the gulf. These observatories were inspected periodically by Baird and his assistant in turn, in circumstances involving severe privation. Baird was promoted captain on 4 April 1874. In 1876 the governor-general in council commended Baird's labours, and in July 1877 instructions were issued for systematic tidal observations at all the principal Indian ports, and at other ports on the coast lines where the results would be of general scientific interest, apart from their usefulness for purpose of navigation. To Baird, who had become deputy superintendent in the great trigonometrical survey department, was entrusted the general superintendence.
Meanwhile, in 1876, Baird was at home, working out with assistance the results of his observations in the gulf of Cutch. In the autumn he read a paper on 'Tidal Operations in the Gulf of Cutch' before the British Association at Glasgow. On his return to India in June 1877 he organised a new department of the survey along the coast lines from Aden to Rangoon, with its centre at Poona, Bombay.
In July 1881 Baird was at Venice as one of the commissioners from India to the third international congress of geography, and there he exhibited a complete set of tidal and levelling apparatus in practical use in an adjoining canal. Baird was awarded the gold medal of the first class.
After some eighteen months on furlough in England, Baird, who had been promoted major on 18 Dec. 1881, resumed his tidal duties in India in March 1883, his field of operations including India, Burma, Ceylon, and the Andaman Islands. On 27 Aug. the great volcanic eruption of Krakatoa, in Java, caused a wave which was distinctly traceable in all the tidal diagrams, and Baird sent a paper on the subject to the Royal Society, of which he was elected a fellow in the following May (Proc. Roy. Soc. No. 229, 1884).
Between July 1885 and August 1889 Baird was temporarily employed as master of the mint at both Calcutta and Bombay, and also as both assistant and deputy surveyor-general of India. He was promoted brevet lieutenant-colonel on 18 Dec. 1888, and on 12 Aug. 1889 became permanent mint master at Calcutta. In that office he re-organised the manufacturing department. In 1895-6, in accordance with his proposals, the government withdrew from circulation worn and dirt-encrusted coinage.
Promoted regimental lieutenant-colonel on 9 April 1891, brevet colonel on 29 Sept. 1893, and substantive colonel on 9 April 1896, he retired from the mint owing to the
