If our eyes only saw frames (IE: 30 images a second), like a single lens reflex camera, we'd see images pop in and out of existance and that would really be annoying and not as advantagous to us in our three dimensional space and bodies.
In the Vienna of the second half of the 18th century, in addition to Haydn and Mozart, three symphonic composers, namely Leopold Hoffmann, Carl Ditters von Dittersdorf and J.B. Vanhal helped further the development of the symphony.
About the middle of the century in Mannheim, Germany, composer and conductor Johann Stamitz (1717-1757) and his followers began to develop the orchestra and the art of orchestration, basing their music on the Baroque homophonic style, but now with chords played in unison rather than contrapuntally.