Get as much detail into your opening sentence as possible

No more than three feet away from Julius (but certainly more than two feet away; perhaps thirty inches – or, in the system preferred by Helen, Julian’s wife, of whom more later, seventy-six point two centimetres – although needless to say, it seemed less) a dog which seemed to be a cross between a doberman and some kind of beagle – its appearance certainly seemed to fit the original meaning of the Old French word “beegueule” (literally, open-mouthed) from which “beagle” is derived – was barking in the key of E-flat and pawing the air in a way which, had there been an invisible miniature piano beneath its claws, might have produced a melody not dissimilar to a free jazz composition of the early sixties or, more likely, a discordant jumble of sharps and flats which, had this been the case rather than being merely a fanciful possibility (which is what it was), would have put Julius’ teeth on edge in a way which the dog’s barking, in the absence of the more musical set of noises just touched upon, was already managing to do.