We can be heard as well, and better, if we pitch our voices on a lower key than if we pitch them on a higher key; and to pitch your voice on a low key requires very much less effort than to strain to a high one.
I can imagine talking with some one for half an hour in a noisy factory--for instance--and being more rested at the end of the half hour than at the beginning.

Because to pitch your voice low you must drop some superfluous tension and dropping superfluous tension is always restful.
I beg any or all of my readers to try this experiment the next time they have to talk with a friend in a noisy street.

At first the habit of screaming above the noise of the wheels is strong on us and it seems impossible that we should be heard if we speak below it.

It is difficult to pitch our voices low and keep them there.

But if we persist until we have formed a new habit, the change is delightful.
There is one other difficulty in the way; whoever is listening to us may be in the habit of hearing a voice at high tension and so find it difficult at first to adjust his ear to the lower voice and will in consequence insist that the lower tone cannot be heard as easily.
It seems curious that our ears can be so much engaged in expecting screaming that they cannot without a positive effort of the mind readjust in order to listen to a lower tone.