SUNSPOT BY Jonathan Polkest Scilly Isles Artist

The cyclic variation of the number of sunspots was first observed by HEINRICH SCHWABE between 1826 and 1843 and led RUDOLF WOLF to make systematic observations starting in 1848.The Wolf number is an expression of individual spots and spot groupings, which has demonstrated success in its correation to a number of solar obseervables.Also in 1848.JOSEPH HENRY projected an image of the Sun onto a screen and determined that sunspots were coolere than the sorrounding surface. WOLF also studied the historical record in an attempt to establish a database on cyclic variations of the past.He established a cycle database to only 1700, although the technology and techniques for careful solar observations were first available in 1610 GUSTAV SPØRER later suggested a 70 year period before 1716 in which sunspots were rarely observed as the reason for WOLF'S inability to extend the cycles into the seventeenth century.The economist WILLIAM STANLEY JEVONS suggested that there is a relationship between sunspots and crises in business cycles.He reasoned that sunspots affect earths weather, which in turn influences crop yields and therefore, the economy.