This is more or less a continuation of one of my earlier posts.
English displays its inimitable idiosyncrasies when it comes to the usage of idioms, phrases and prepositions in more mystifying ways than one. What else can I say, when it rains heavily it is said to rain cats and dogs? Have you ever seen these animals falling in hordes from the skies? I haven't, of course and not even kitten and puppies. The etymology enthusiast that I am, I started exploring the various possibilities for the origin of this phrase. Thankfully, being the handy aid that the worldwide web is, I came across the following link when I googled for the phrase: http://www.phrases.org.uk/. Although the site does not provide any etymological evidence, it nevertheless puts forth a number of improbable folk etymologies to explain the phrase.
