In the year before he took his own life in 1878 he transferred his advocacy to the Kuro Siwo, a Pacific Ocean current analyzed in the 1850s by the hydrographer Silas Bent.
I året før tog han sit eget liv i 1878, overførte han sin argumentation til Kuro Siwo, en Stillehavsstrøm analyseret i 1850-erne af hydrografen Silas Bent.