The 1839 uniform regulations prescribed this plate for the Corps of Topographical Engineers. The oval inner plate, which contains the prescribed eagle, shield, and the letters "U S" in Old English, is struck in medium weight copper and gilded. This inner plate is soldered to a cast-bronze and gilded tongue which in turn is brazed to a cast-bronze belt attachment. The oval outer ring, bearing the prescribed "CORPS OF TOPOGRAPHICAL ENGINEERS" in Roman capitals, is cast in brass and gilded. To the inner edge of this outer ring are brazed two curved seats for the inner oval. The whole is brazed to the belt attachment, also cast in brass and gilded. ¶ In view of the large and somewhat elaborate cap plates as well as shoulder-belt plates adopted by both the Regulars and Militia early in the 19th century, it is somewhat surprising that apparently neither component had ornamentation on its cartridge boxes until the Ordnance Regulations of 1834 prescribed a very ornate design embossed on the leather flap.[96] Certainly there was precedent for such, for both the British and German mercenary troops of the Revolution and the British and Canadian troops of the War of 1812 wore metal ornaments on their cartridge boxes. At least partial explanation for this omission may lie in one of Callender Irvine's reasons for rejecting brass cartridge boxes in favor of leather ones: "The leather ... affords no mark for the enemy to sight at. The brass ... would afford a central object, as regards the body of the Soldier, and one which would be seen at a great distance to fire at."[97] Why Irvine did not object equally to the large white and yellow metal cap and shoulder-belt plates as targets is unknown. In any case--with a possible few Militia exceptions such as a Militia cartridge box with a plate bearing the likeness of Washington in silver, both about 1835--the 1839 model oval plates were the first to be worn. [Footnote 96: _See Military Collector and Historian_ (June 1950), vol. 2, no. 2, pp. 29-30.] [Footnote 97: Letter dated June 29, 1813, from Irvine to Secretary of War (Records AGO).]