Levelling staff (c.1950) of height 2 ft 9 in capable of being raised to 6 ft 3 in. It was designed for use in surveying in height restricted areas. It has a “roller blind” mechanism which means it can be extended to any length and still retain accuracy. At the top of the staff secured to the innermost section is a spring roller which allows the face to be unwound and rewound when the staff is raised and lowered respectively.
This staff was originally owned by Dudley Technical College and used to instruct students. It was “saved from the skip” by the donor when in 1968 the college disposed of its old mine surveying equipment.
An early description of this staff is provided by William Stanley:
A portable mine staff designed by Mr. G. J. Jee, is said to be a useful staff for colliery work. It is constructed in three lengths, sliding one into the other. The bottom length of three feet is graduated in the ordinary way. The top of this length has a band attached to it, painted to continue the lower division of the staff upwards. The other end of the band passes over a roller attached to the top division of the staff. The roller contains a spring which keeps a constant tension on the band. By extending the lengths of the staff and clamping them, the staff may be lengthened out any distance to 9 feet. The weight of the staff is 5 lbs. (Ref: Stanley, William F. SURVEYING AND LEVELLING INSTRUMENTS Theoretically and Practically Described. E & FN Spon, Ltd, London. 1914 p159. See https://www.gutenberg.org/files/63834/63834-h/63834-h.htm)