Just to reintroduce this thread, I found a wonderful old book—in terrible shape but very useful--A TRAMP TRIP (How to see Europe on Fifty Cents a Day), written in 1886 by Lee Meriwether and published in 1887 by Harper & Brothers of New York.
And again with apologies, because of the complicated subject matter, in this thread I’ll usually be posting in English only. But please, any and all contributions are very welcome, no matter how expressed.

--------------------------------------------------------------------------------------
Mr. Meriwether is still in Italia, still in Napoli…
“In Naples there are no dairies, no milkman to wake you at 6 A.M. with a big bell…Instead, men walk from street to street leading cows by strings, and when a customer comes the cow-man stops and milks the desired quantity. I purchased a small tin bucket, and every morning and evening took a short stroll until I saw a man with a cow, from whom I got a quart of milk, and on this, with bread and figs, made an economical and nutritious meal. One would imagine this method would absolutely preclude surreptitious watering of the milk. I thought so, but soon found my mistake.
“I noticed the milk I drank was peculiarly thin, yet, as I had stood by while it was milked I was at a loss to understand the cause. Could it be that the cows drank too much water? One day the mystery was explained. It happened that when I came across my cow-man he was milking for an Italian. I was surprised when I saw the Italian suddenly step up and squeeze the cow-man’s arm, and still more surprised when, as a result thereof, I saw a stream of water spurt from the cow-man’s sleeve.
“I mentioned this incident to the American consul, who told me it was a very common trick. Cow-men keep a bag of water under their coats, letting it down into the milk through a rubber tube concealed in the sleeve. When detected, a shrug of the shoulders, a ‘Santa Maria, what difference?’ is the cool reply; when not detected, the Neapolitan cow-man silently laughs as he squirts water through his sleeve and sells it to you at six cents a quart.”
….Mr. Meriwether is talking in terms of American money and American measures for the convenience of his readers…6 (U.S.) cents per quart (liter) of milk, but he was actually spending 30 centesimi, perhaps like this: