Be sure and mix the lettuce and oil well together before you add any vinegar.

The reason of this is that if you add the vinegar first it would soak into the lettuce leaves, making one part more acid than another.

Having well mixed up the lettuce and oil, add half a tablespoonful of vinegar.

Mix it once more, and the salad is dressed.
In France they always add to the lettuce, before it is dressed, two or three finely chopped fresh tarragon leaves.

Dried tarragon can be used, but it is not equal to fresh.