Musical note indicated by placing the symbols in the key signature, which then apply implicitly to all occurrences of corresponding notes. Explicitly noted accidentals can be used to override this effect for the remainder of a bar. A special accidental, the natural symbol , is used to indicate an unmodified pitch. Effects of key signature and local accidentals do not accumulate. If the key signature indicates G, a local flat before a G makes it G (not G), though often this type of rare accidental is expressed as a natural, followed by a flat () to make this clear. Likewise (and more
Pitch pipe marked the notes of either the chromatic scale or the diatonic scale, and by setting it to the correct position, the indicated note will be produced when the instrument is blown. Pitch pipes come in all sorts of shapes and sizes. Pitch pipes of this sort were most often used in the 18th and 19th centuries in churches which had no organ to give the opening note of a hymn. They are now quite rare, and hardly ever used for what they were intended, but may still be used as an alternative to a tuning fork. They are also useful