But one must still be wary  the fact that although we've got this nice electric gadget, that we drop the probe into a bucket of water and it gives us er a salinity  it is still entirely dependent on this ratio  and this ratio is based on the constancy of composition which is very good for open ocean waters but breaks down in coastal waters where erosional processes, where fresh water additions and the sediment loads of the rivers  may actually alter this ratio, okay?