question: For which invention are both Christian Friedrich Schönbein, a the German-Swiss chemist and William Robert Grove, the Welsh judge and physical scientist given credit?
answer: fuel cell
context: Title: William Robert Grove
  Passage: Sir William Robert Grove, PC, FRS FRSE (11 July 1811 – 1 August 1896) was a Welsh judge and physical scientist.  He anticipated the general theory of the conservation of energy, and was a pioneer of fuel cell technology.  He invented the Grove voltaic cell.
  Title: All-purpose yardage
  Passage: All-purpose yards or all-purpose yardage is an American football and Canadian football statistical measure.  It is virtually the same as the statistic that some football leagues refer to as combined net yards.  In the game of football, progress is measured by advancing the football towards the opposing team's goal line.  Progress can be made during play by the offensive team by advancing the ball from its point of progress at the start of play known as the line of scrimmage or by the defensive team after taking possession of the football via a change of possession (such as punt, kickoff, interception, punt block, blocked kick or fumble).  When the offensive team advances the ball by rushing the football, the player who carries the ball is given credit for the difference in progress measured in rushing yards.  When the offensive team advances the ball by pass reception, the player who catches the reception is given credit for the difference in progress measured in reception yards.  Although the ball may also be advanced by penalty, these yards are not considered all-purpose yards.  Progress lost via quarterback sacks is classified variously.  Thus, all-purpose yards is a combined total of rushing yards, receiving yards, and all forms of return yards only.  Some sources do not specify which types of return yards count toward this total because the most common forms of return yards are kick and punt return yards.
  Title: Wilhelm Weith
  Passage: Wilhelm Weith (9 May 1846, in Bad Homburg vor der Höhe – 29 November 1881, in Ajaccio) was a German-Swiss chemist.
  Title: Christian Friedrich Schönbein
  Passage: Christian Friedrich Schönbein (18 October 1799 – 29 August 1868) was a German-Swiss chemist who is best known for inventing the fuel cell (1838) at the same time as William Robert Grove, Robert Cumming and his discoveries of guncotton and ozone.
  Title: Yards from scrimmage
  Passage: Yards from scrimmage is an American football and Canadian football statistical measure.  In the game of football, progress is measured by advancing the football towards the opposing team's goal line.  Progress can be made during play by the offensive team by advancing the ball from the point of progress at the start of play known as the line of scrimmage.  When the offensive team advances the ball by rushing the football, the player who carries the ball is given credit for the difference in progress measured in rushing yards.  When the offensive team advances the ball by pass reception, the player who catches the reception is given credit for the difference in progress measured in reception yards.  Although the ball may also be advanced by penalty these yards are not considered yards from scrimmage.  Progress lost via quarterback sacks are classified variously by league of play with rules having changed over time within some leagues.  The total of rushing yards and receiving yards is known as yards from scrimmage.  This definition of yardage differs from total offense which gives credit for passing yardage to the person throwing the football rather than receiving the football.
  Title: Pompejus Bolley
  Passage: Pompejus Alexander Bolley (7 May 1812 in Heidelberg – 3 August 1870 in Zürich) was a German-Swiss chemist known for his work in dye chemistry.
citations: William Robert Grove Christian Friedrich Schönbein