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.
In late medieval England, symphony was used in both of these senses, whereas by the 16th century it was equated with the dulcimer. In German, Symphonie was a generic term for spinets and virginals from the late 16th century to the 18th century.