Various have been the opinions upon the difference of speed between a well-bred greyhound and a racehorse if opposed to each other. Wishes had been frequently indulged by the sporting world that some criterion could be adopted by which the superiority of speed could be fairly ascertained, when the following circumstance accidentally took place, and afforded some information upon what had been previously considered a matter of great uncertainty. In the month of December 1800 a match was to have been run over Doncaster racecourse for one hundred guineas, but one of the horses having been withdrawn, a mare started alone, that by running the ground she might ensure the wager; when having run about one mile in the four, she was accompanied by a greyhound, which joined her from the side of the course, and emulatively entering into the competition, continued to race with the mare for the other three miles, keeping nearly head and head, and affording an excellent treat to the field by the energetic exertions of each. At passing the distance post five to four was betted in favour of the greyhound, when parallel with the stand it was even betting, and any person might have taken his choice from five to ten; the mare, however, had the advantage by a head at the termination of the course.