About that lamp....

The only known surviving example of Trouvé’s portable electric safety lamp (conceived and constructed by the inventor early in 1884) is on show at Teylers Museum in Haarlem, the Netherlands.

Reading perhaps the only known purchase receipt for a Trouvé instrument, the latter was purchased for Dfl 46 on November 10, 1884 in Haarlem, from a factory/shop owned by F. W. Funckler. The shop sold Barometers, Thermometers and Microscopes etc. The lamp had more or less the same price as a barometer. On the receipt, dated April 1885, it says in Dutch that the shop supplied a workman who worked 224 hours a 0, 20 cents pro hour.

So approximately for the price of one lamp you could also get someone who worked 224 hours. This made Trouvé’s lamp rather expensive!