After some brief study at King's College, Aberdeen, he entered in 1841 his brother's counting-house in London, and there set about collecting materials for a history of astronomy.
The only available part of its equipment was a six-inch transit-circle by Ertel,[note 1] and with it Grant made a long series of meridian observations, the results of which were embodied in A Catalogue of 6415 Stars for the Epoch 1870, published at Glasgow in 1883.
A nine-inch Cooke equatorial was mounted under Grant's supervision in 1863, and was employed by him for observations of planets, comets, and double stars.
He joined the Himalaya expedition to Spain for the total eclipse of 18 July 1860, and from his station near Vittoria watched the disclosure of the chromosphere and prominences, the true nature of which he had been one of the first to infer.
The Leonid meteors of 1866 and 1868, the Andromeda of 1872 and 1885, and the ingress of Venus at the transit of 1882 were observed by him, and formed the subjects of communications to the Royal Astronomical Society.
Many articles by him were inserted in Knight's English Cyclopaedia, and he contributed as well to the Astronomische Nachrichten, the Comptes Rendus, and the Proceedings of the Philosophical Society of Glasgow, of which body he acted as president during three years.