Cleaning out some old books, I came across something I’d completely forgotten I’d bought. “Manners for Men” by Mrs. Humphry, published 1897.

From the chapter “In the Street”:

In meeting acquaintences a nod is sufficient for a male friend, unless his age or position is such as to render it advisable to raise the hat. Should a lady be with the acquaintance, any man meeting them must raise his hat. So must the individual walking with the lady. The etiquette of bowing is a simple one. Male acquaintances always wait for acknowledgement on the part of the female, as well as from those men who are their superiors in age or position. But this does not mean that they are shyly to look away from them and to ignore them. On the contrary, they must show clearly by their manner that they are on the look-out for some sign of recognition and are ready to reply to it. Shyness often interferes with this and makes a young man look away, and this is occasionally misconstrued as indifference and resented as such. The calm, quiet, collected expression of face that suits the occasion is not achieved at once. Sometimes the over-anxiety to make a good impression defeats itself, producing a blushing eagerness better suited to a girlish than a manly countenance. This, however, is a youthful fault that is not without its ingratiating side, though young men view it in themselves and each other with unbounded scorn. This sentiment of self-contempt is a frequent one in young people of both sexes. Their valuation of themselves varies as much as the barometer and is as much affected by outward causes. After a “snub”, real or fancied, it goes down to zero, but as a rule it speedily recovers itself and in most young men enjoys an agreeable thermometer of 85° or so in the shade!