M. F. B. Dausse visited FW several times to study instruments and copy meteorological observations. Dausse urged FW to share these with D. F. J. Arago, who is concerned at delay in publishing survey results. Please notify R.S.L. that Arago's official request will arrive soon. Encloses copy of FW's 15 Apr. 1841 letter to Arago. New rain gauge. Problems with anemometer and dipping needle. Will visit Cape Agulhas with Thomas Maclear to make magnetic observations.