What is the name of the works that Bennet's friend who he went on country walks with said was "three of Bennett's loveliest pictures"?
In May 1836 Bennett travelled to Düsseldorf in the company of Davison to attend the Lower Rhenish Music Festival for the first performance of Mendelssohn's oratorio St Paul. Bennett's visit was enabled by a subsidy by the piano-making firm of John Broadwood & Sons. Inspired by his journey up the Rhine, Bennett began work on his overture The Naiads (Op. 15). After Bennett left for home, Mendelssohn wrote to their mutual friend, the English organist and composer Thomas Attwood, "I think him the most promising young musician I know, not only in your country but also here, and I am convinced if he does not become a very great musician, it is not God's will, but his own".
After Bennett's first visit to Germany there followed three extended visits to work in Leipzig. He was there from October 1836 to June 1837, during which time he made his debut at the Gewandhaus as the soloist in his Third Piano Concerto with Mendelssohn conducting. He later conducted his Naiads overture. During this visit he also arranged the first cricket match ever played in Germany, ("as fitting a Yorkshireman" as the musicologist Percy M. Young comments). At this time Bennett wrote to Davison:[Mendelssohn] took me to his house and gave me the printed score of [his overture] 'Melusina', and afterwards we supped at the 'Hôtel de Bavière', where all the musical clique feed ... The party consist[ed] of Mendelssohn, [Ferdinand] David, Stamity [sic] ... and a Mr. Schumann, a musical editor, who expected to see me a fat man with large black whiskers. 
Bennett had been at first slightly in awe of Mendelssohn, but no such formality ever attached to Bennett's friendship with Robert Schumann, with whom he went on long country walks by day and visited the local taverns by night. Each dedicated a large-scale piano work to the other: in August 1837 Schumann dedicated his Symphonic Studies to Bennett, who reciprocated the dedication a few weeks later with his Fantasie, Op. 16. Schumann was eloquently enthusiastic about Bennett's music; in 1837 he devoted an essay to Bennett in the Neue Zeitschrift für Musik, praising amongst other works Bennett's Op. 10 Musical Sketches for piano, "three of Bennett's loveliest pictures". The essay ends: "For some time now he has been peering over my shoulder, and for the second time he has asked 'But what are you writing?' Dear friend, I shall write no more than: 'If only you knew!'" Bennett however had from the outset some reservations about Schumann's music, which, he told Davison in 1837, he thought "rather too eccentric".
Op. 10 Musical Sketches