In the published scientific literature one seldom finds a paper describing a failure. However, occasionally some new experimental effect is presented in a respectable scientific journal (i.e. it has passed the scrutiny of strict referees) and later on, in the light of repeated and improved experimental evidence, the claimed effect has turned out to be non-existent (i.e. the claim was 'false'). I do not intend to discuss the epistemoligical implications of such claims, but will present, in outline, a few typical cases from a broadly 'sociological' point of view. This is a very preliminary essay for a larger work in preparation. I will refer only to published material, and will only describe 'important' experiments. There are innumerable cases in the measurement of, say, atomic, nuclear and subnuclear particles, where several groups measure the same parameter and their results differ by more than the stated limits of error: thus, one or more of the measurements must be 'wrong'. But usually not much fuss is made about this. With the refinement of methods, the results more and more converge towards an accepted common value, and the problem quietly solves itself. If not all 'false' publications provoke response, it may be because they are 'unimportant': that is to say, they are not pertinent to any fundamental theory, law or model. By this definition, important 'pseudo-effects' cannot go unnoticed. On the contrary, they immediately stir up a controversy, with several groups involved: and, as we shall see later, they are typically dealt with in a relatively short time (up to two or three years). One purpose of this Note is to indicate how the physics community behaves in such cases. I have chosen examples from the quite recent history of physics. Although I thus deny myself the benefit of lengthy hindsight, I will look at a more relevant and accessible portion of history, whose witnesses are still with us. The types of 'false' effects are chosen in order to exemplify various interesting situations: (a) an attack on a well-established modern theory (special relativity); (b) discovery of a predicted new force (gravitational waves); (c) indirect attack on the basis of modern quantum electrodynamics;