I owe this one to my colleague Paul Davies, who unearthed a set of requirements from 1888, 132 years ago, by the UK company Barr and Stroud. Barr and Stroud was a market leader in optronics, particularly rangefinders and submarine periscopes, latterly IR imaging and lasers. It got taken over by Pilkington the glass manufacturers, then Thomson CSF, which became Thales. The requirements:

RANGE FINDER:

1. The instrument must be strong and simple, and must not require frequent adjustment, nor extraordinary precautions against the exigencies of Field Service and effects of climate and weather.
2. It must be possible for one infantry soldier to carry the entire apparatus, in addition to his rifle and ordinary equipment, both on the march and in action.
3. A person of ordinary intelligence and normal vision must be able to become an efficient range taker after a month’s training.
4. The system must be suitable for the observation of moving objects, especially troops of all arms in the usual formations up to 1200 yards distance.
5. It must be practicable to make at least four observations per minute, with an average error, at 100 yards, not exceeding 4 percent of the range.
6. The range must be read in yards without recourse to calculation.
7. The number of observers for each instrument or set of instruments must not exceed two.
8. Other considerations being equal, preference will be given to those instruments which
9. Can find the range of fixed objects up to 2500 yards with the greatest rapidity, but with an error not exceeding 100 yards; this to be effected either by the normal mode of operations, or with the aid of extra appliances.
10. Require only one observer.
11. The instruments submitted for trial must be complete, with full description, and instructions for use.
12. Proposals must be addressed to …

Paul said “Bear in mind that this was written in 1888 – Good mix of functional and performance requirements, human factors and logistics requirements, and best of all NO design requirements! Even the beginnings of a Value Model and a ConUse. OK some need a bit more quantification, but I’ve seen a lot worse, from trained procurement executives, in the last 20 years. How did we lose the capability to write them?”