High-pressure area of their associated cold fronts. The stronger the pressure difference, or pressure gradient, between a high-pressure system and a low-pressure system, the stronger the wind. The coriolis force caused by the Earth's rotation is what gives winds within high-pressure systems their clockwise circulation in the northern hemisphere (as the wind moves outward and is deflected right from the center of high pressure) and counterclockwise circulation in the southern hemisphere (as the wind moves outward and is deflected left from the center of high pressure). Friction with land slows down the wind flowing out of high-pressure systems and causes wind to
High-pressure steam locomotive sealed ultra-high-pressure circuit that simply transferred heat to a high-pressure circuit, by means of heating coils inside a high-pressure boiler. If this latter was fed with ordinary water, scale could form on the outside of the heating coils, but it could not cause overheating because the ultra-HP tubes were quite capable of withstanding their internal steam temperature, though not the firebox flame temperature. The sealed ultra-high-pressure circuit ran at between , depending on the rate of firing. The HP boiler worked at approx , and the low-pressure boiler at . The UHP and HP boilers were of a water tube