The Editor of the Scientific American acknowledges, with much pleasure, the receipt of original papers and contributions upon the following subjects:

• On Rheumatism. By A.R.E.
• On Postage Stamps. By E.B.
• On Boiler Explosions. By G.B.B.
• On Reaching the North Pole. By J.H.S.
• On Heating Street Cars. By P.T.
• On a Hybrid Fruit, By R.S.B.
• On an Air Vessel. By J.T.R.

Also inquiries and answers from the following: E.B.M. - F.F.F. - N.B.H. - B.B. - O.F. - R.V.J. - F.M. - N.B.C. - C.F.E. - W.T. - C.W.C. - T.F. - C.A.S. - S.N.M. - J.R.D. - P.J.D.S.