It is only in the case of continuous and considerable depressions that the cause is in action long enough to produce discernible effects.
The most common, and by far the most important, case where the depression in one trade causes depression in all others, is that of depressed agriculture.

When the agriculture of the world is ill off, food is dear.

And as the amount of absolute necessaries which a people consumes cannot be much diminished, the additional amount which has to be spent on them is so much subtracted from what used to be spent on other things.

All the industries, A, B, C, D, up to Z, are somewhat affected by an augmentation in the price of corn, and the most affected are the large ones, which produce the objects in ordinary times most consumed by the working classes.

The clothing trades feel the difference at once, and in this country the liquor trade (a great source of English revenue) feels it almost equally soon.