Account of a comparison of magnetic instruments at Kew Observatory

Last July, M. T. Moureaux, of the Parc Saint-Maur Observatory, near Paris, brought over to England the travelling instruments employed in his magnetic survey of France, and a comparison was made between these and the standard magnetic instruments at Kew Observatory. At the expressed desire of the Kew Observatory Committee, I submit on their behalf a brief account of the comparison and its results. The comparison serves to connect the standard instruments at Kew Observatory with the standard French instruments at Parc Saint-Maur, the latter, as M. Moureaux has had the goodness to inform me, being in excellent agreement with his travelling instruments.