Dating information.
W.T. & Co. 1857-1901
W.T Co.  1901-

1880 -- no mention of custom lettered medicine glasses in catalogs.
1887 -- #7 & #12 embossed
W.T.-Tacoma Bonney & Hahler Druggists Tacoma,W.T. {sm circa 1885 nothing}
W.T.-Tacoma Compliments Of Stewart's Pharmacy Tacoma W.T. {sm circa 1886 W.T.& Co.}

1897 -- #40 spoon
NJ-Millville Graduated No. {W.T. & Co. Monogram} 40 Medicine Spoon

Size #18 conical
Before 1907-
Cook’s Pharmacy Okmulgee, I.T. {conical} {before 1907}
I.T. Poteau
Noble & Bird Druggists Poteau, I.T. {conical} {before 1907}

Acid Etched 1904-
-Palace Drug Store J.F. Greenlee Phone 26 Alva, Okla. Circa:1912
OK-Pond Creek
-B.C. Sahm Prescription Druggist Pond Creek, Okla. Circa:1904

Silk Screened
W.T. & Co. markings
After 1891-1901
McKinley Tariff Act
Country Of Origin
marks needed.

W.T. & Co. AA U.S.A.
W.T. & Co. AB U.S.A.
W.T. & Co. AC U.S.A.
W.T. & Co. AD U.S.A.
W.T. & Co. AF U.S.A.
W.T. & Co. AG U.S.A.
W.T. & Co. AH U.S.A.
W.T. & Co. AI  U.S.A.
W.T. & Co. AJ U.S.A.
W.T. & Co. AK U.S.A.
W.T. & Co. AL U.S.A.
After 1901

W.T. Co. T U.S.A.
W.T. Co. AH U.S.A.
W.T. Co. AJ U.S.A.
W.T. Co. AL U.S. A.
W.T. Co. AM U.S.A.
W.T. Co. AN U.S.A.
Single Letter Marks
1870's early 1880's
B Fultonville, N.Y.
C Watkins, N.Y.
E Evanston, WY {1870's}
H Springfield, OH
I  Deposit, N.Y.
J Chillicothe, OH
O Grafton, D.T. {1870's}
Most Large Size Cups Seem To
Have No Markings Or A
Single C
These cups weigh 2 1/2 ounces.

Large size with W.T. & Co. marks
weigh 1 1/2 ounces.

My thoughts are cups with single
letter markings were made by
different glass company's.
W.T. & Co.
Early Marks Before 1891
{No U.S.A.}
Dates that are known when the cups were in use.
W.T. & Co. B  Atlanta, GA
W.T. & Co. M Fort Plain, N.Y. {1872}
W.T. & Co. O Salem Ogn. {1880 on}
W.T. & Co. R  Sheboygan, WI
W.T. & Co. S  Logan City, UT
W.T. & Co. Q Juarez, Mexico
W.T. & Co.
After 1901
Transition Marks-Before the
Lower works in SO. Millville
Upper Works Millville Proper

W.T. & Co. E  U.S.A.
W.T. & Co. T  U.S.A.
W.T. & Co. W U.S.A.
The listings below will help you to date your dose cups.
Millville, N.J.
Original Plant
Millville proper
Lower works in South Millville (formerly known as Schetterville)
CO-OP F.G. Co.
Co-Operative Flint Glass Company of Upland, Indiana, they were closed by 1911. By that time they were called the Co-Operative Glass Company.
The mark is found on the following small size cups.
Woodard Clark & Co.  mono Portland Or. {CO-OP F.G. Co. small }
Lengfeld’s 202 Stockton St. S. F. Pharmacy  { backwards N in Lengfield’s} {CO-OP F.G. Co. small }
Single letters were used at
Millville Proper Plant.
Double letters were used at the Lower works in So. Millville, NJ.
Dose Cups with the Hazel Atlas mark are after 1901. ------->
Dose Cup Dating Page #2