One might ask why he was moving to the United States Army Signal Service, but this is much more obvious when we realise that at the time it ran the national weather service, and that it became the U.S. Weather Bureau under civilian control in 1891.
Isa maaaring magtanong kung bakit siya lumipat sa Pilipinas Army Signal Service, ngunit ito ay marami pa halata kapag realise namin na sa oras na ito ang bumangga sa pambansang panahon na serbisyo, at na ito ay naging ang US Weather Bureau sibilyan sa ilalim ng control sa 1891.