Letter from M J M [Micaiah John Muller] Hill, 18 Ferncroft Avenue, Hampstead, London, to [Joseph] Larmor Thanking Larmor for his letter and stating that he can always take λ=0 as his boundary surface for the vortex. From this he outlines his mathematical reasoning for inside and outside the vortex, commenting on the nature of the problem and referring to p. 219 of his spherical vortex paper. He gives equations, but asks Larmor not to take any more trouble in the matter. 25 January 1906