If you could post close up shots of the whistle, or see any markings, it'd really help us out.

Based on what I can see, it's very similar to a MacGregor Goldsmith #6 but can't say for certain as of yet :
http://whistlemuseum.com/2009/05/13...es-in-the-usa--bubble-top-part-1-at-work.aspx (scroll down to about 3/4 of the page)
If it's Goldsmith of P. Goldsmith & Sons, Cincinnati, they've have been around since 1875 and best known for making sports equipment :
http://webcache.googleusercontent.c...d=9&hl=en&ct=clnk&gl=us&source=www.google.com
MacGregor Sporting Goods also makes the same; however, MacGregor didn't buy out / merge with Goldsmith until 1962. The whistle looks much older than that.
In the below picture, there are also the initials "W.H." on the whistle. The only whistle maker I know of is W. Horstmann out of Philadelphia / New York :
W.H. Horstmann & Sons Phila ~ 1843 to 1863
W.H. Horstmann & Co Phila ~ 1859 - 1863; NY ~ 1850-52
Horstmann Bros. & Allien NY ~ 1852-77
Horstmann/Philadelphia ~ 1893-1935