Ups and downs you will see, heights and depths, in our fiery course together by Thomas de Quincey

Here pause, reader ! Imagine yourself seated in some 
cloud-scaling swing, oscillating under the impulse of lunatic 
hands ; for the strength of lunacy may belong to human 
dreams, the fearful caprice of lunacy, and the malice of 
lunacy, whilst the lictim of those dreams may be all the 
more certainly removed from lunacy; even as a bridge 
gathers cohesion and strength from the increasing resistance 
into which it is forced by increasing pressure. Seated in 
such a swing, fast as you reach the lowest point of depres- 
sion, may you rely on racing up to a starry altitude of 
corresponding ascent. Ups and downs you will see, heights 
and depths, in our fiery course together, such as will some- 
times tempt you to look shyly and suspiciously at me, your 
guide, and the ruler of the oscillations, Here, at the point 
where I have called a halt, the reader has reached the lowest 
depths in iny nursery afflictions. From that point according 
to the principles of art which govern the movement of these 
Confessions, I had meant to launch him upwards through 
the whole arch of ascending visions which seemed requisite 
to balance the sweep downwards, so recently described in his 
course.