* Translation by Serge Roube

A) Ebony

There is a great variety of cases spanning from the rarest woods to more classical ones.
While Thomas de Colmar was alive, until 1870, the cases were mostly made of Ebony and/or Ebony veneer. Delicately inlaid with threads of brass, they have “Aritmometre” written on the lid.  Inside, a holding area allows you to store a stylus, some pegs to indicate the decimal places, a bit of paper...

Arithmometer T1860

Medium and long cases (Circa 1875)

After 1870, the Black Cases are mostly found with 20 digit machines.  We have one example of a Payen Arithmometer with a black case, which makes it quite scarce.  Additionally, they no longer have the same quality of manufacturing and a black lacquer replaces the beautiful ebony inlay!

B) Mahogany

Mahogany first appear on a prototype of 1850.  The case is made of a beautiful blond mahogany! One distinctive feature is the grooves carved in the wood to allow the cylinders to rotate! The cabinet-maker must have messed up the dimensions!
We find a series of Mahogany cases around 1864-1865 on the luxury models of the catalog, but usually, this wood was not used much! However, we find it on the long 20 digits machines from Payen!

Boite T1850

Boite T1852 A

Circa 1864

Long case – Payen P3

C) Oak

Oak was one of the favorite woods used on the last Thomas and was used almost exclusively for the Payen production.  These cases were solid and cheaper to manufacture!
Around 1900, a clever system allows the user to angle the case, making it more comfortable to operate.

S/n 1371 (circa 1876)

Thomas S/n 2065 (circa 1884)

Boite Payen P2 S/n 2785 (circa 1893)

Payen P4 S/n 5519 (circa 1907)

Models / Wood	Ebony	Mahogany	Oak	Pictures
T1848	A	-	-
T1850	B	A	-
T1852	AB	-	-
T1856	A	-	-
T1858	A	-	-
T1860	A	-	-
T1865	ABC	A (5x0x10)	AB
T1878	BC	-	AB
P1	-	-	AB
P2	C	-	AB
P3	-	C	AB
P4	-	A	BC