John E. Whitcomb and George F. Ballou were both machinists at the American Watch Co., but left in 1872 to form their own watch-lathe manufacturing company, Ballou & Whitcombe, in Boston. However, the venture lasted only two year for, in 1874, George Ballou left to start another venture and John Whitcombe and Henry R. Fisher moved the business - to the then centre of American watch and clock making - Waltham, in Massachusetts where they traded as J.E.Whitcombe & Co.
(Ref: Dervan, Andrew H.  The Chronicle of the Early American Industries Association, Inc; Delmar Vol. 70, Iss. 4,  (Dec 2017): 161-166)
Looking similar to the No.2 watchmakers' lathe by Stark - and with which it was initially confused - this example of a Ballou & Whitcombe carries, on the end of its bed, in tiny, faded letters Ballou & Whitcombe, Boston Mass. The other end of the bed is stamped No.2 -presumably, this was the Model 2, leading one to speculate if there might also have been a No.1 and a No.3.
The only other Ballou lathe known is a beautifully engineered backgeared and screwcutting front-way type very similar to the Rivett 8-inch precision - though between 1875 and 1887, George Ballou registered several significant  patents relating to watchmakers' lathes, as follows:
Gear-cutting device for lathes (this shows an aspect of the Ballou lathe)
Improvement in slide-rests for metal-turning lathes
Improvement in chucks and centerers
Drilling-fixture for lathes
As production of the Ballou & Whitcome lathe lasted for only two years, these are rare machine with the one below the only known example. If you are lucky enough to own another example, the writer would be very interested to hear from you..

In 1872 John E. Whitcomb and George F. Ballou left American Watch Co., where they had worked as machinists, to start a lathe manufacturing company in Boston. In 1874 George Ballou left that company for another venture, and John E. Whitcomb and Henry N. Fisher moved the business to Waltham, Massachusetts, and continued manufacturing lathes under the name J. E. Whitcomb and Company. The Whitcomb lathe received high praise for its use of a hardened steel spindle and hardened steel bearings. In 1876 Ambrose Webster (Figure l) resigned from the American Watch Co. and joined John E. Whitcomb (Figure 2) to form the American Watch Tool Company. Ambrose Webster had apprenticed as a machinist at the Springfield, Massachusetts, government arsenal. In 1857 he was hired by the American Watch Co. as its first trained machinist and became an assistant general superintendent.1
Webster and Whitcomb built and equipped their factory in Waltham. The Waltham Free Press reported, 'Whitcomb Watch Tool Co. is building a brick factory across from crayon factory."2 By 1890, the factory was the largest and most complete in the world for manufacturing lathes, watchmaker's tools, and machinery (Figure 3). In 1878 Webster designed the No. l'/> lathe, with various attachments, that proved very popular. He used his extensive experience working in a watch factory and making watch tools to design the new lathe, considering size and proportions of the spindle, chucks, and the tailstock's form. Its lathe replaced the company's two original lathes: No. 1 and No. 2. No. 1 was too small and No. 2 was too large for watch repairers.3 Company records indicate that 152 various-size lathes were sold in 1880,650 in 1887, and 721 in 1889. In 1888, Webster designed a lathe known as 'Webster-Whitcomb" that had improvements over the one he had designed earlier. 'A firstclass lathe was somewhat expensive, but it was always durable and was the cheapest in the end" (Figure 4).4