command over figures. His son and his grandchildren possess this visualising power, and they also inherit considerable calculating abilities. A study of Bidder's system, partly natural and partly elaborated, cannot fail to be of value to all who wish to improve their calculating powers; but the power with which he used it will not readily be rivalled.
The lad's peculiar talents, evinced by the rapidity with which he answered arithmetical questions requiring the performance of intricate calcidations, soon drew public attention to him, and his father found it more profitable to carry him about the country and exhibit him as the ' calculating phenomenon ' than to leave him at school. Fortunately for him his powers attracted the attention of several eminent men, by whom he was placed at school, first at Camberwell, and afterwards at Edinburgh. His education was completed at the university of Edinburgh, where, in 1822, he obtained the prize given for the study of the higher mathematics by the magistrates of Edinburgh. It is pleasant to note that many years afterwards, in 1846, Bidder founded a bursary or scholarship for poor students of 40l. a year, which he named the 'Jardine Bursary,' in joint recognition of the university where he had obtained his education, and of the eminent man by whose influence he had been sent thither. After a brief employment in the Ordnance Survey and a still briefer trial of a clerkship in the office of a life assurance company, he took regularly to engineering. He was employed on several works of more or less importance, and became associated with Robert Stephenson in 1834 in the London and Birmingham railway. A year or so later this brought him into parliamentary work, and here he soon found full scope for his marvellous powers of calculation. He could work out on the instant, and in his head, calculations which would take most men a considerable time and require the use of paper and pencil. He was never disconcerted, and he was always minutely accurate. So great did his reputation soon become that on one occasion an opposing counsel asked that he should not be allowed to remain in the committee-room, on the ground that ' nature had endowed him with qualities that did not place his opponents on a fair footing.' Numerous stones are still extant, attesting the skill with which he would detect a flaw in some elaborate set of calculations, thereby upsetting an opponent's case, or would support his own conclusions by an argument based on mathematical data, possibly only then put before him. Probably nowhere else could he have found so suitable a field for the exercise of his peculiar talents as in a parliamentary committee-room, nor is it easy to conceive a man better adapted to this special sort of work.
But, besides his parliamentary practice, Bidder was also much employed in the actual practice of his profession, and as engineer constructed numerous railways and other works at home and abroad. The Victoria Docks (London) are considered one of his chief constructive works, and, after railway matters, hydraulic engineering principally engaged his attention. But he was more or less interested in a large proportion of the subjects coming within the wide range of engineering science. He was the originator of the railway swing bridge, the first of which was designed and erected by him at Reedham on the Norwich and Lowestoft Railway; he was one of the founders of the Electric Telegraph Company (the first company formed to provide telegraphic communication), and he was associated, either as adviser or constructor, in many of the great engineering works carried out during the time covered by his professional career. He died at Dartmouth on 20 Sept. 1878, and was buried in the churchyard of Stoke Fleming, an adjacent village.
[A very full life is given in Proc. Inst. C.E. lvii. 294; other interesting details will be found in the paper on Mental Calculation, ibid. xv. 251.]
BIDDLE, JOHN (1615–1662), unitarian, was son of a tailor of Wotton-under-Edge, Gloucestershire, where he was baptised on 14 Jan. 1615. He early showed himself a youth of great promise. He was fortunate enough to come under the notice of George, eighth Lord Berkeley, who allowed him, with other scholars, an annual exhibition of ten pounds, though he was not yet ten years old. 'He was educated,' says Wood, 'in grammar-learning in the free school, by John Rugg and John Turner, successive teachers.' Under the latter he 'outran his instructors, and became tutor to himself.' While still a schoolboy he 'english'd ' 'Virgil's Bucolics and the two first Satyrs of Juvenal.' These were printed in 1634, and dedicated to 'John Smith, Esq., of Nibley,' Gloucestershire, and the 'Mecsenas of the Wottonian muses.' He likewise 'compos'd and recited before a full auditory,' in the beginning of 1634, 'an elaborate oration in Latin for the funeral of an honourable school-fellow.' He was a dutiful son to his mother who was left a widow in straitened circumstances at this period.
He proceeded in 1634 to Oxford, and was entered a student of Magdalen Hall. 'And for a time,' says Anthony à Wood, 'if I
