It is especially in amplifying, clarifying, and solidifying this taste that the second group of volumes, dealing with the media of musical production, will be useful to the unprofessional reader. A knowledge of the construction of instruments and of the style appropriate to each, as determined by its peculiarities and exemplified in its literature, is a great aid both to the appreciation of excellence and to the detection of shoddiness. A simple example will make this clear. Every one who has watched a pianist play a waltz knows how appropriate and convenient for the piano is that kind of accompaniment which has been called the 'dum-dum-dum’--where the left hand first sounds the bass and then strikes twice a chord completing the harmony and at the same time marking the rhythm. This is an excellent piano device, because it does these three needful things in the simplest possible way. What shall we say, however, when laziness or incompetence, writing a waltz for orchestra, borrows this piano device without change, as it does constantly in the popular music of the day? Evidently enough, what was well fitted to the piano is ridiculous for an orchestra: for here it gives the bass instruments a series of detached notes without coherence or interest, and condemns the unfortunate players who provide the middle parts to repeat an endless 'dum-dum, dum-dum’ which outrages all musical instinct. Or, again, we sometimes hear piano pieces in which the harmonies are arranged in solid chords, as in the hymn-tune familiar in the protestant church. Why the effect should be so singularly vapid we do not know until we think of the peculiarities of the instruments involved. Voices, especially in large groups, as in congregational singing, move slowly, sustain well, and show their quality best when disposed in broad masses. Hence the appropriateness to them of these deliberate chords. But the piano, on the contrary, sustains very poorly, achieves fullness of volume only by means of rapid utterance, and is in short at its very worst in the hymn-tune style. Piano tone requires to be split up into many facets, to be carved, so to speak; but vocal tone is like those substances, such as colored marble, which show their texture best in the block. Recently there has been much controversy as to the appropriateness of organ transcriptions of orchestral works. No doubt the organ can render the notes of a symphony quite as well as the poor overworked piano, but a rudimentary knowledge of the mechanism of the organ will show us where lies its special capacity--in the sustaining and rolling up of great masses of tone, and not at all in that more intimate expressiveness through swelling and fading and through accent in which the violin is peerless. The organ is magnificent in a Bach fugue, unsatisfactory in a Beethoven symphony, ridiculous in a popular dance. Thus on all sides we see that style depends on the medium, and that a sensitive taste will no more detach a