This pair of oil on canvas paintings show a mid to late 18th and an early 19th century soldier and officer respectively. The officer is shown at a barracks with a sentry box to the background and the enlisted man is in a country setting. It is very possible that they were originally panels from a screen that may have shown British Army uniforms through the ages. This would explain the difference in period of the uniforms, the size of the painting etc.
They are painted with a charming naive quality. Mid to late 19th Century.