Simplicity, clearness of style, grace and playfulness are the leading features of Haydn's symphonies. There are few of the more notable of them in which his command over the science of his art is not delightfully manifested. Haydn is invariably lucid, always finished to the highest point, always logical and always free from display for the mere sake of display. It is a prevailing fault to dwell too persistently on the cheerful simplicity of Haydn's music and to forget how serious and profound he could be when occasion demanded. These latter qualities are nobly manifested in his more important symphonies in those portions of them devoted to the "working out." Such symphonies as appeared before Haydn fixed the form and showed the capacity of that species of composition have wholly disappeared. It would perhaps be over dogmatic to assert that had it not been for Haydn the symphonies of Mozart and of Beethoven would not have been what they are; but it is certain that Haydn gave the impulse to both in as far as their symphony writing is concerned.
Of the quartet Haydn may be justly called the inventor, and it is in this phase of his art that he may be most profitably studied. The quartet was, as Otto Jahn truly says, "Haydn's natural mode of expressing his feelings," and it is in the quartet that Haydn's growth and progress in his art are most strikingly illustrated. Their influence on music has been greater than that exerted by his symphonies. Here he is seen in his full and his best strength, and it is here too that his extraordinary creative powers are most brilliantly emphasized. When these works first appeared they were sneered at by the pedagogues of the day, but by-and-by more respect was shown to them even by their earlier antagonists, for it was seen that the quartet was not only susceptible of depth of sentiment and seriousness of treatment, but that musical learning also had in them a field for its finest development. These quartets, from the opportunities they afforded for performance in the family circle, exercised great influence in raising the standard of taste, and in their educational aspects they were thus of the highest service. They crystallized form and in essence may be looked on as the parent of all the serious and so-called classical music that has been composed since. The progeny may only distantly resemble the parents, but the form establishes beyond all cavil the family resemblance.