I have recently managed to get a copy of Floyd Clymer's historical motor scrapbook (written in 1944) which is more or less what is says it is - a melange of old advertisements and features about cars, motorcycles and a few aircraft - mostly American as one would expect from Floyd Clymer.

One thing that I was suprised at was that, up to about 1909, most advertisers aksed that respondents apply for a copy of the manufacturer's catalogue but from that year onwards, most (but not all) manufacturers invited respondents to request a copy of their catalog.

I had always imagined that the US spelling shift took place when Noah Webster produced his first dictionary, around 100 years previously. Was catalogue an exception?

Incidentally, it is salutory to realise how few of the 2000 plus US manufacturers who were active in the first quarter of the last century have survived: I could only spot Ford, Cadillac, Chrysler, Harley Davidson and Briggs & Stratton (who now only make portable engines of course).

I'm pretty sure the older spelling survived into the 1960s in some parts of the USA, and was common in the 1950s. I'll bet Tinman can find citations in no time flat! Tinman, do yer stuff!

Webster's 1828 dictionary spells the word catalogue and has no entry for catalog so it doesn't seem to be one of his reforms.

I have a 1994 Random House dictionary that lists both, but with the bowdlerized version listed first.

Then I suspect it's simply a spelling shift that has followed Webster's examples, such as programme changing to program. I concede that there's no real need for the additional letters in catalogue - the pronunciation must be the same for either spelling since "g" is always hard at the end of a word.