In a review of the July 1955 edition of the French dowsing journal, La Radiesthesie pour Tous, there appeared a technique to recover stolen goods. It is a good example of the reach of dowsing applications attempted by European dowsers in contrast to their British counterparts at that time (and perhaps even today).
The review is brief, but it appeared to work by planting a in the mind of the thief, the idea to return the articles which they had stolen. The account contains some terms which might be difficult for the modern treader to decipher.
By “regulating” the pendulum, I believe the author is referring to adjusting the length of the pendulum string until a reaction was obtained. This was a technique common at this time, each object sought had a characteristic pendulum length.
There is a reference to “drawings which heal”. There is no previous reference to this term in the review, but it appears that the method involved using the pendulum to create a pattern on paper, which would then act as a dowsing sample. This seems to be a kind of ritual, perhaps it better aided the dowser to focus in on the target (or thief in this case).
The drawing is then “magnetised”, which reflects the commonly held idea that the dowsing reaction was due to some kind of electromagnetic effect, but in fact it is simply a case of allowing the sub conscious mind to reach out, so to speak, to the target.
If we take this at face value, and there is no particular reason not to, then we have an example illustrating that we simply do not know the limits of psi, of which dowsing is simply an application.