英语翻译In Europe,before the introduction of the mechanical cloc

英语翻译
In Europe,before the introduction of the mechanical clock,people told time by sun (using,for example,shadow sticks or sun dials) and water clocks.Sun clocks worked,of course,only on clear days; water clocks misbehaved when the temperature fell toward freezing,to say nothing of long-run drift as the result of sedimentation and clogging.Both these devices worked well in sunny climates; but in northern Europe the sun may be hidden by clouds for weeks at a time,while temperatures vary not only seasonally but from day to night.
其中这一句 to say nothing of long-run drift as the result of sedimentation and clogging.怎么翻译 漂流了怎么又沉积 阻塞了呢,还有 to say nothing of 这个词组放这里也翻译不通啊 +分