Notes on pressure is a quest item from While Guthix Sleeps obtained in Movario's base. The notes are a hint as to how to exit the base even though the "Look-at" option only reads: "Some notes about pressure... probably just boring old stuff anyway." If you lose the notes during or after the quest, you can reobtain them in the base.
~ A Treatise on pressure ~
During my may adventures, I've had occasion to notice the effect of mass upon a compressible fluid or solid. In some planes, for instance, differences in gravity may affect one's weight, but relative pressure remains constant, as the fluid or solid being measured is affected in the same way.
With these experiences I've deduced that, just as weight can be measure, pressure can be recorded as a reflection of mass. in the first instance, my unit of measurement is quite arbitrary, but suits my needs. the pressure applied to a cubic yard of air by the heat of a typical dragon's flame I have dubbed as 1 dragflam (D) and broken that down into 1,000 tickits (t).
Of course, it is difficult to coerce a person into a container to be scorched by a dragon, and the only practical purpose I can thus far determine is to measure vertical pressure that is, the pressure afforded from a combination of mass and gravity.
Therefore, a small amount of weight, say that produced by a human carrying seventeen units of coal produces around 38 tickits (38t) of vertical pressure.
These are reasonable assumptions to make regarding pressure, at least until a universally agreed scale of measurement exists.
Other standard vertical pressures include
rune platebody - 9t
mithril crossbow - 5tfire battlestaff - 2t.