Dating Lachenal Anglo Concertinas: A More Accurate Method

By William Meredith (cinesound@nyc.rr.com), Owner Cinesound Company, NYC

The formula presently used to determine the approximate date of manufacture of a Lachenal Anglo Concertina, 1850 + (Serial Number/4070), appears to be based on somewhat flawed assumptions. Although the date for the start of manufacturing, 1850, is probably correct, the concept of a consistent output of 4,070 instruments every year for 86 years, yielding a total of 350,000 concertinas, must be seriously questioned.

For comparison, a chart¹ of all the concertinas ever made by the Wheatstone company gives us an insight into the wide swings in annual production that took place over its 127-year history. It is therefore highly likely that Lachenal experienced similar variations in output, not the constant production implied by the above formula.

Wheatstone Concertina Production by Year 1830 - 1957 (All Models) - Total Production = 36,680

In his article on this subject², David Aumann lists five confirmed serial number-date combinations:

Although this is not a massive sample, it does provide a method for more accurately determining a Date from a Serial Number, with the assumption that there was one instrument made for each consecutive serial number.

The logic is as follows:

Between 1850 and 1860 there were 11,653 concertinas made, or 1,165 per year (11,653/10 years)

Between 1860 and 1868 there were 6,544 concertinas made, or 818 per year (6,544/8 years)

Between 1868 and 1895 there were 33,283 concertinas made, or 1,232 per year (33,283/27 years)

Between 1895 and 1908 there were 88,895 concertinas made, or 6,838 per year (88,895/13 years)

This is all we can derive from the known data, but I’m going to make one more addition to the list based on observation. So far, there does not appear to be a Lachenal Anglo Concertina with a serial number higher than 201000. Until some surface, I propose adding the following to the list:

Between 1908 and 1936 there were 60,625 concertinas made, or 2,165 per year (60,625/28 years).

Lachenal Concertina Production by Year 1850 - 1936 (Anglo Models) - Total Production = 201000

Combining these estimates with the known combinations gives us the following:

We can now use a new formula to determine the Date of Manufacture much more accurately:

Take the Serial Number of the instrument in question and subtract the closest LOWER Known Serial Number. Divide by the Number per Year and add the result to the Known Date corresponding to the subtracted Serial Number.

A few examples will help clarify this procedure.

For an instrument with serial number 74681:

Subtract 51480 (the closest LOWER Known Serial Number) from 74681 leaving 23,201 (the actual number of instruments manufactured between the two serial numbers).

Divide 23,201 by 6838 (the estimated number of instruments being made each year during the period from 1895 to 1908) which gives 3.39 (the number of years it would take to make 23,201 instruments at a rate of 6838 per year)

Adding 3.39 to the benchmark date of 1895 (Known Date corresponding to Known Serial Number 51480) gives an estimated year of manufacture of 1898 - 1899 for serial number 74681.

A second example for an instrument with a serial number of 16278:

16278 minus 11653 equals 4625 which, divided by 818 yields 5.65. Adding 5.65 to 1860 gives a date of 1865 - 1866 for the instrument.

Although constant output assumptions are still being made in these calculations, they are in much more reasonable amounts and cover far more limited time periods. Further refinements could also be made by adjusting the yearly output estimates. As seen in the Wheatstone chart, production was probably slower in the initial years, and varied across time more than these limited data points can show.

However, even with these limitations, until additional verified Serial Number-Date combinations become available, I believe this method is significantly better than the previous formula for obtaining more accurate dating information for Lachenal Anglo Concertinas.

¹ Chart was based on information from: http://www.harbour.demon.co.uk/tina.faq/conc-ap1.htm
² http://www.concertina.net/guide_lachenal.html