S.M. Aikman Co. Made 
G.W. Woodwards patented threaded globe design of April 5th 1864 is a take on the Mason jar lid patent of 1858
Woodward licensed his patent out to 3 companies of the time.
This is a seldom seen guarded version which also unthreads along with the top and bottom.
Patent date of April 5th 1864  is embossed on the globe along with G.W. Woodward.
( very strong cast ) 
Fount is a one piece  bayonet skirt with finger loop and a No.1 J. Sangster 1862 burner.

Condition  - is excellent, lightly cleaned brass with some patina.
Only notable condition issues is two small stress cracks in the lower body as pointed out , does not effect operating use.
One dent on the fount.
No other visible condition issues present. 

Beautiful piece ready for display. 

** has not been oil tested **