Baird & Tatlock Wheatstone Bridge resistance box in mahogany case. 29cm long, signs of use, not tested. Baird and Tatlock 45, Renfrew Street, Glasgow, makers of scientific instruments In 1881 Hugh Harper Baird set up business in Glasgow. In 1890 Baird moved to Hatton Garden, London, where he opened a small warehouse and office, later adding a small workshop, to supply laboratory equipment. In 1897 Business split in two. '...the Partnership heretofore subsisting between us the undersigned Hugh Harper Baird and John Tatlock carrying on business as Dealers in Pure Chemicals Laboratory Furnishings &c. at No. 14 Cross-street Hatton Garden London and at No. 40 Renfrew-street Glasgow and at No. 10 Drummond-street Edinburgh under the style or firm of Baird and Tatlock has been dissolved by mutual consent as and from the 30th day of April 1896. The said Hugh Harper Baird will continue to carry on business at the above address, in London on his own account under the style or firm of Baird and Tatlock. The said John Tatlock will continue to carry on business, at the above addresses in Glasgow and Edinburgh on his own account under the style or firm of Baird and Tatlock A resistance box, also known as a decade box or resistance substitution box, is a device that provides precise and variable electrical resistance in electronic and electrical circuits, allowing for quick and easy adjustment of resistance values. The main application of the resistance box is to control the specific value of current to flow through the circuit. The advantage given by the resistance box is that the variable resistances are available at one point. If any circuit requires variable resistances, then there is no need of replacing the resistor. A Wheatstone bridge is an example of voltage dividers with two voltage dividers in parallel. The "bridge" is the difference in p.d. between the two voltage dividers.