On a trip to Wales in 2010 I found this steel tape in an antiques shop. The tape is signed "J.B. Tibaut Desimpelaere Bruxelles" and is therefore of Belgium origin.

A 1922 trade catalogue states that J.-B. Tibaut-Desimpelaere are "...Opticiens, constructeurs d'instruments de précision..." and have been active at least from 1898 until 1922 in Brussels.^1,2 Although they are known as instrument makers and had a workshop it seems that they also were re-sellers as a Graphometer# with their signature is known of a very general design.⁴ It is found unsigned like the one in my collection and signed by other period makers/sellers like one by Ducretet.

The way the signature is added to the instrument is very similar to how this was done with the pantometer in my collection (i.e. by slightly rotating the characters of the winds and placing the signature symmetrically below it).

The tape is made of steel and wound on an oak frame. It is 10 metres in length and divided by punch holes every centimetre, every fifth of which has a larger diameter. Every 10th centimetre it is filled with a brass rivet, and an additional brass washers every 20 centimetres (see figure 5). Every meter small brass plates are attached on both sides of the tape, showing complementary figures running from 1 to 9, indicating the metres (see figure 6).

The handles bear the maker's signature "J.B. Tibaut Desimpelaere Bruxelles" (see figure 4). They are made of brass and have grooves to fit the pins that would be used to stake out and measure a trajectory (see figure 3).

Steel tapes tend to break easily when not carefully used and this particular example has no less than 12 repaired sections. Special sets were available to repair steel tapes and obviously those have been used numerous times on this tape.⁵ At least three different types of tape can be distinguished along this steel tape (see figure 7).

The handles are identical on both sides, this in contrast to the Ahrend steel tapes in my collection. Quite often steel tapes and chains had the grooves on the inside at one end of the tape or chain and at the outside at the other end.

Normally the groove on the outside was used by the man ahead of the tape, while the man at the rear of the tape would use the handle with the groove on the inside. The main reason for having the grooves on different sides of the handle is to reduce observation errors due to differences in pin thickness. The groove in the handle would have the same diameter as the pins used with it, but when the diameter of the pins is wrong a tape or chain with grooves at the same side of the handle would produce errors (i.e. each section being measured slightly too short or too long).⁶ This is thus prevented by having the grooves on one side of the handle at one end and the other side at the other end.

A set of 11 or 6 pins would have been used with the tape to count the sections. The fore man would have all pins at the start of the measurement, pushing one in the ground every whole length of the tape. The rear man would pick up the pins as they went on. As soon as the fore man had no pins left, both men came together to exchange pins and they knew that another section of 10 or 5 tape lengths had been measured.⁷

Steel tapes started to be used around the 1840's. Initially they were made of short sections riveted together as there was no method yet to harden and temper continuous strips of steel.⁸ In 1842 Chesterman, the firm I have a survey chain from, made his first steel tapes that consisted of five foot sections.⁸

In 1853 steel tapes were three times as expensive as chains than half a century later,^9,10 which may be an indication for growing demand for the tape during this period. They were preferred above chains as the latter could not be easily calibrated, while chains had to be laid out carefully so that they were fully stretched. For this reason one was not allowed to use chains for accurate measurements in the second half of the 19^th century.¹¹ They have been in continual use until at least the 1960's as they could still be purchased from Chesterman in 1962.¹²