Fascicle D-1 "Machines" — CNAM Laboratory Testing Fees

In this document

This printed fascicle "D-1 Machines" constitutes an official price list of the Conservatoire National des Arts et Métiers (CNAM) Testing Laboratory. It details, test by test, the fees applied for testing different types of machines.

Boilers and heating appliances

The document lists the prices for testing industrial boilers (500 to 750 francs depending on the evaporation rate, standard duration "8 hours") p. 18, heating boilers (450 to 900 francs depending on the calories produced) p. 19, as well as hot water and steam radiators, priced per test point p. 19-20, and gas or coal radiators/stoves p. 20.

Engines

Detailed are the rates for testing steam engines p. 20-21 and internal combustion engines, with fees varying according to the power in CV (from less than 5 CV to 100 CV) and according to the requested determinations (effective power, indicated power, consumption) p. 21. The Laboratory specifies that it has "dynamometric dynamos", a "complete set of Charles Renard wind vanes", and can test aviation engines using braking propellers p. 21. Spark plug tests are also priced p. 21.

Hydraulic machines, fans, propellers

The fascicle covers hydraulic motors and pumps p. 22, fans, compressors and vacuum pumps p. 22, air filters p. 22, aerial propellers and thrusters p. 23, pneumatic hammers (with rates according to one, two or three pressures) p. 23 and wind vanes p. 23.

Automobiles, suspensions and shock absorbers

Page 24 prices the measurement of power at the rim of automobiles (300 to 350 francs depending on the number of speeds) p. 24, as well as the "Suspensions and shock absorbers and other special tests on automobiles; road tests", counted by the hour (60 francs for the first four hours, 50 francs thereafter) with an installation fee of 300 francs per device p. 24. Flat rates are provided for a morning, an afternoon or a full day of testing p. 24.

Transmissions and others

The fascicle ends with the rates for testing belts, pulleys, speed reducers, bearings, bushings and ball bearings p. 24-25, then seals, stuffing boxes and brake linings p. 25-26, before referring to fascicles A-7, A-8 and A-9 for measuring instruments p. 26.

Context

In the 20th century, the CNAM had a recognized testing laboratory, solicited by industry for independent mechanical performance measurements. In the automotive world of the time, manufacturers like Citroën could call upon this type of organization to validate or certify the performance of their mechanical components, particularly suspension systems — a field on which Paul Magès, who joined Citroën in August 1925 and became deputy head of the Super-Contrôle (autobiographical notes), would work from the 1940s onwards with the invention of the hydropneumatic suspension (first drawings on 17 February 1944, hydropneumatic suspension drawings), used notably on the Citroën DS presented in 1955.

Archivist's view

This price list mentions no brand or proper name: it is a generic document, kept by Magès as a practical reference to know the costs and procedures for independent tests — in particular the "Suspensions and shock absorbers" section p. 24, directly linked to his field of expertise at the Citroën Super-Contrôle.

Its presence alongside the Hotchkiss-Laffly vehicle test report and the general brochure of the CNAM Laboratory suggests that it belonged to a technical documentation file compiled around these external tests, probably consulted to evaluate the cost of road tests or suspension components.

The dating remains uncertain: no element of the document (neither cover page, nor printed date) allows the year of publication of this fascicle to be specified.