Dear Richard,
i can't recall where i read this and i don't know how the "Merrick font" looks like, but i do remember most "experts" say the standard that comes closest to what you are seeking for is the german standard DIN 1451 (alt/ old, outdated version, prior 198x) and it is the version called "Mittelschrift D". Also note, another possible variety could be the "Engschrift". And also hand painted/ written varieties of "sans-serif-type" are possible.
Here is a place where you can find the complete font set according to your IT equipment:
http://www.myfonts.com/fonts/urw/mit...+&case=default
And here is a sample: