The 1851 uniform regulations called for a "castle of yellow metal one and five-eighths inches by one and one-fourth inches high" on both the coat collar and the hat of "Engineer Soldiers." This specimen, struck in brass, conforms exactly to the descriptions and drawing in the Horstmann publication of the regulations. CAP INSIGNIA, DRAGOON OFFICERS, 1851 _USNM 604879 (S-K 1024). Figure 50._ [Illustration: FIGURE 50] Comprising crossed sabers of gold, with edges upward, this insignia is similar to the well-known device worn by the Regular cavalry as late as 1953. ¶ In 1846 the Regiment of Mounted Riflemen was organized to consolidate the northern route to the Pacific by establishing and manning a series of posts along the Oregon Trail.[80] The outbreak of the War with Mexico postponed this mission and the unit was diverted to the theater of operations. Shortly after the regiment was constituted it was authorized to wear a forage cap device prescribed as "a gold embroidered spread eagle, with the letter R in silver, on the shield."[81] No surviving specimen of this insignia is known, and there seems some doubt that it was ever actually manufactured.[82] [Footnote 80: Act of May 19, 1846 (_Military Laws_, pp. 371-372).] [Footnote 81: General Order No. 18, June 4, 1846, War Department (photostatic copy in files of division of military history, Smithsonian Institution).] [Footnote 82: Insignia of the riflemen are discussed by Townsend and Todd, pp. 2-3.] CAP INSIGNIA, OFFICER, REGIMENT OF MOUNTED RIFLEMEN, 1850 _USNM 604854 (SK 999). Figure 51._ [Illustration: FIGURE 51] In 1850 the regiment was given a "trumpet" hat device. Officers were to wear "a trumpet, perpendicular, embroidered in gold, with the number of the regiment, in silver, within the bend."[83] This trumpet is also known in metal imitation-embroidery. The prescribed regimental number, which is illustrated in the Horstmann publication of the regulations (pl. 15), is not included on the device, probably because there was but one such unit in the Regular Establishment. [Footnote 83: General Order No. 2, February 13, 1850, War Department (photostatic copy in files of division of military history, Smithsonian Institution).] CAP INSIGNIA, ENLISTED, REGIMENT OF MOUNTED RIFLEMEN, 1850 _USNM 62053-M (SK-1806). Figure 52._ [Illustration: FIGURE 52] The same general order that gave rifle officers a gold-embroidered trumpet prescribed for enlisted men a similar device to be of "yellow metal." This insignia lasted but one year for the men in the ranks, being unmentioned in the 1851 regulations. Shoulder-Belt and Waist-Belt Plates