Brookfield made a huge number of bottles for may different companies as testified by at least one article from the past. In a Brooklyn Eagle article from 1975 a reporter mentioned visiting Brookfield and seeing a huge room full of bottle molds. But brookfield rarely put a makers mark on the bottles.

I have what I consider to be quite a familiarity with the "hand" of some of the engravers at Brookfield after writing the CREB guidebook which is meticulous on lettering, punctuation etc.

AT the recent Columbia City show Josh Dondorf had this bottle. I turned it over and saw the same style of 5 (in "15") that I have seen a number of times in 45 CLiff ST. on CREB crowns. So I went looking. I found other Maltines on eBay where the numbers on the bottom were shown, and I saw a lot of numbers in styles I am used to seeing. I could match an 6 (or 9?), 8, 18, 7, and 17 that appear to be from the same hands. The only number I could find that was not something I am used to is a large 2...and it was on a different style of Maltine bottle.