There is a click when the pistol is well at full-cock, which tells you the pistol is properly cocked, the hammer or cock goes slightly beyond full-cock and then comes into place by a click. (See quotation from Byron’s Don Juan on a [later page].)
To put to half-cock is the most ticklish of all and is the cause of most pistol accidents.
The thing to do is to let the hammer fall to just below half-cock and then bring it back to half-cock. If it falls too low it fires the pistol, if it does not click it has not properly got to half-cock.
Still holding the barrel of the pistol in the left hand and the grip in your right (keep the pistol carefully pointed at the butt where an accidental discharge would do no harm), put your right thumb on the hammer. When you have a firm touch of it so that it cannot escape you as it falls, put your first finger on the trigger and press, but only for an instant.
The hammer will fall but you must keep it from falling fast, by holding back with your thumb. Lower the hammer down to just below half-cock back to half-cock and then release your thumb hold.
If the hammer went its full fall it would explode the cartridge. With a rebounding hammer, the hammer falls and instantly springs back to half-cock. Therefore in letting a rebounding lock down from full to half-cock, if you are able to restrain it well during the first part of its descent, even if it slips from your thumb before it is quite at half-cock, the rebound overcomes the downward fall and it rebounds to half-cock without actually exploding the cartridge because it does not quite reach it.
Half-cock is the safest position for a loaded single-shot pistol but not safe enough to carry in a pocket or holster loaded. For that, it needs a safety lock to hold it at half-cock.
As you gain confidence you will find that, with a rebounding lock (such as all duelling pistols of full-size calibre by the best makers have), it requires very little holding back at the hammer in letting it down to half-cock and the hammer remains at half-cock by itself, without any click.
With an ordinary hammer which remains down when it is fired (like many single-shot pistols of American make or the .2 bulleted caps of the “Flobert Pistol”), the hammer must be kept firmly held until it is below half-cock, and then brought to half-cock where it will click, as it also does at full-cock.
The great advantage of an automatic pistol is that it does not have this click and so does not give warning to an adversary and is not apt to go off by accident when being put at safe.