Erich Moritz von Hornbostel and Curt Sachs published their 'Systematik der Musikinstumente: Eine Versuch' as a draft, a basis for discussion in the second half of 1914. By the time it appeared, everybody was engaged elsewhere, so that the discussion never happened. As a result, we are left with it as it stands. It has many deliberate gaps in it, which H&S left for discussion with other scholars. In one case, the xylophones, they gave examples of how it may be expanded. This is left for us to emulate with other instruments. As it stands, its torso remains the only possible international system for the classification of instruments because, being a numerical system, it is totally culture-free. A number can be translated into any language on earth, with the same meaning worldwide. It is also free of any cultural baggage of the use of instruments, of their colour, their size, or any other of the aspects that have been used in more local systems in the past. There is a number of serious problems, particularly how one inserts newly discovered types of instrument. One major problem, now probably irremediable, is the reed instruments, which they classified by reed, an element that in museums is often missing, and means splitting those pairs where the treble has a single reed and the tenor a double reed, rather than by bore, which controls the acoustical behaviour.