Sinclair was deposed from the presidency in 1798, and succeeded by Lord Somerville. He again was succeeded by Lord Carrington, under whose presidency the board offered premiums (the first of £200), owing to the high price of wheat and consequent distress, for essays on the best means of converting certain portions of grass land into tillage without exhausting the soil, and of returning the same to grass, after a certain period, in an improved state, or at least without injury. The general report, based on the information derived from these essays, states that no high price of corn or temporary distress would justify the ploughing up of old meadows or rich pastures, and that on certain soils well adapted to grass age improves the quality of the pasture to a degree which no system of management on lands broken up and laid down can equal. In spite of this, the cupidity of landowners and farmers, when wheat was a guinea a bushel or at prices near it, led to the ploughing up of much splendid grass land, which was never laid down again until, perhaps in recent years, owing to the low price of grain; so that some of the land at all events has, owing to bad times, returned to the state best suited to it.
The board looked upon the enclosure and cultivation of waste lands, which in England they estimated at 6,000,000 acres,[508] as a panacea for the prevailing distress, and after much opposition they managed to pass through both Houses in 1801 a Bill cheapening and facilitating the process of parliamentary enclosure. This Act, 41 Geo. III, c. 109, 'extracted a number of clauses from various private Acts and enacted that they should hold good in all cases where the special Act did not expressly provide to the contrary.' Another benefit rendered to agriculture was the establishment in 1803 of lectures on agricultural chemistry, the first lecturer engaged being Mr., afterwards Sir Humphry, Davy, who may be regarded as the father of agricultural chemistry.
In 1806 Sinclair was re-elected president, and his second term was mainly devoted to completing the agricultural surveys of the different counties, which, before his retirement in 1813, he had with one or two exceptions the satisfaction of seeing finished. Though over-impetuous, he rendered valuable service to agriculture, not only by his own energy but by stirring up energy in others; as William Wilberforce the philanthrophist said, 'I have myself seen collected in that small room several of the noblemen and gentlemen of the greatest properties in the British Isles, all of them catching and cultivating an agricultural spirit, and going forth to spend in the employment of labourers, and I hope in the improvement of land, immense sums which might otherwise have been lavished on hounds and horses, or squandered on theatricals.'