Sir Bertrand, which had impressed him very strongly in his boyhood, in his Book for a Corner (1849) ascribes the authorship of the tale to Dr. Aikin, commenting on the fact that he was “a writer from whom this effusion was hardly to have been looked for.”  It is probably safe to assume that Walpole, who was a contemporary of the Aikins and who took a lively interest in the literary gossip of the day, was right in assigning Sir Bertrand to Miss Aikin,[31] afterwards Mrs. Barbauld, though the story is not included in The Works of Anne Letitia Barbauld, edited by Miss Lucy Aikin in 1825.  That the minds of the Aikins were exercised about the sources of pleasure in romance, especially when connected with horror and distress, is clear not only from this essay and the illustrative fragment but also from other essays and stories in the same collection—­On Romances, an Imitation, and An Enquiry into those Kinds of Distress which Excite Agreeable Sensations.  In the preliminary essay to Sir Bertrand an attempt is made to explain why terrible scenes excite pleasurable emotions and to distinguish between two different types of horror, as illustrated by The Castle of Otranto, which unites the marvellous and the terrible, and by a scene of mere natural horror in Smollett’s Count Fathom.  The story Sir Bertrand is an attempt to combine the two kinds of horror in one composition.  A knight, wandering in darkness on a desolate and dreary moor, hears the tolling of a bell, and, guided by a glimmering light, finds “an antique mansion” with turrets at the corners.  As he approaches the porch, the light glides away.  All is dark and still.  The light reappears and the bell tolls.  As Sir Bertrand enters the castle, the door closes behind him.  A bluish flame leads him up a staircase till he comes to a wide gallery and a second staircase, where the light vanishes.  He grasps a dead-cold hand which he severs from the wrist with his sword.  The blue flame now leads him to a vault, where he sees the owner of the hand “completely armed, thrusting forwards the bloody stump of an arm, with a terrible frown and menacing gesture and brandishing a sword in the remaining hand.”  When attacked, the figure vanishes, leaving behind a massive, iron key which unlocks a door leading to an apartment containing a coffin, and statues of black marble, attired in Moorish costume, holding enormous sabres in their right hands.  As the knight enters, each of them rears an arm and advances a leg and at the same moment the lid of the coffin opens and the bell tolls.  Sir Bertrand, guided by the flames, approaches the coffin from which a lady in a shroud and a black veil arises.  When he kisses her, the whole building falls asunder with a crash.  Sir Bertrand is thrown into a trance and awakes in a gorgeous room, where he sees a beautiful lady who thanks him as her deliverer.  At a banquet, nymphs place a laurel wreath on his head, but as the lady is about to address him the fragment breaks off.