Measuring systems were in use by the Greeks, and before that by the Egyptians whose pyramids could not have been designed and constructed without reliable measuring systems. By the time of the Roman Empire, the measuring standards were carefully preserved in the temples and emperors' palaces to safeguard their integrity. With the disintegration of the Roman Empire, the uniform system of measurement fell into disuse.

Whereas in basic mathematics, the science of quantity, units are not of primary importance the fundamental properties of arithmetic, algebra, geometry, trigonometry, dynamics, etc, are not dependent upon the existence of any particular set of units. For instance, the Pythagorean theorem relating the squares on the sides of a right-angled triangle, would be true in Euclidian geometry for any units of length. The progress and extension of the electric telegraph made it essential for those responsible for the construction and operation of the lines to have a practical knowledge of the system. It became clear, however, that there was a large gap between the students' knowledge of the discoveries of Volta and Galvani, of Oersted and of Faraday, and the work of the practical electricians who had to obtain practical results by communicating their knowledge to others. The development of electrical units and measuring standards from their inception in the 19th century is directly linked with advances made in scientific and engineering applications.

At the meeting of the British Association held in York in 1881, with Sir William Thomson present, the delegates discussed the forthcoming Inter national Electrical Congress to be held in Paris. The firm hope was expressed 'that other nations might agree to the system of units and standards which the British Association Committees had evolved, chiefly under Thomson's inspiration since 1862'. That autumn, Thomson crossed over to Paris as one of the British members forming part of the 250 delegates from 28 countries represented at the Congress, which lasted from 15 September to 19 October 1881. The Electrical Exhibition held at the same time as the Congress was an outstanding success and drew electrical contractors from all parts of the world including the United States. For the first time in Europe, the nearly one million visitors were able to see all that the electrical industry could provide in the way of lighting, telegraphy and telephone systems.

Colonel R.E.B. Crompton CB, FRS (1845-1940), a close friend of Kelvin, had the rare distinction of being an honorary member of the three senior engineering institutions in Britain. Following military service, mainly in India where he did much to develop mechanical traction, in 1876 be became a practising engineer. An outstanding pioneer in the fast developing electrical industry particularly in the electric lighting sector, then in its infancy, as a designer and manufacturer of dynamos his fertile brain and boldness in introducing new designs brought him considerable success.

The important issue of standardization of screwthreads - where the need for fastening devices in all types of apparatus or machinery has always been self-evident - was if anything even slower in Great Britain and the United States than was the case with the recognition of the metric system. Essentially, the question of international screwthread standards could only be completely resolved once the metric system had been accepted on a worldwide basis.

Today, the International Electrotechnical Commission (IEC) is the authority for world standards in electrical and electronic engineering. One important function of the 41 National Committees of the IEC, represented in more than 200 specialised committees, is the compiling of the International Electrotechnical Vocabulary (IEV) containing over 100,000 terms in nine languages, with definitions in French, English and (since 1970) Russian. The IEV forms the basis for international communication in electrotechnical fields and as such, is an invaluable tool for science, trade and industry. The constant evolution of electrotechnical terminology calls for the introduction of new terms or the elimination of outdated nomenclature: this is an essential task of the IEC in keeping abreast of developments taking place in industry.

In this appendix, a list of Colonel R.E.B. Crompton's patents during 1878-1899 is given, including the Patent No., date and title.