CONTENTS. 

 VOL. XIV. 



Page 



On a Colloid Acid, a Normal Constituent of Human Urine. By William 

 Marcet, M.D., F.R.S 1 



Account of Observations of Atmospheric Electricity at King's College, 

 Windsor, Nova Scotia. No. II. By Joseph D. Everett, M.A., F.R.S.E., 

 Professor of Mathematics in King's College, N.S 10 



Notes of Researches on the Acids of the Lactic Series. No. II. Action of 

 Zinc upon a Mixture of Iodide of Ethyl and Oxalate of Methyl. By 

 Edward Frankland, F.R.S., and B. F. Duppa, Esq 17 



Preliminary Note on some Aluminium Compounds. By George Bowdler 

 Buckton, F.R.S., and William Odling, M.B., F.R.S 19 



On Bubbles. By Frederick Guthrie, Esq., Professor of Chemistry and 

 Physics at the Royal College, Mauritius 22 



Note on the Invisible Radiation of the Electric Light. By John Tyndall, 

 F.R.S 33 



Note on a New Object-glass for the Microscope, of higher magnifying 

 power than any one hitherto made. By Lionel S. Beale, M.B., F.R.S., 

 F.R.C.P., Professor of Physiology and of General and Morbid Anatomy 

 in King's College, and Physician to King's College Hospital 35 



Researches on Solar Physics. Series I. On the Nature of Solar Spots. By 

 Warren De la Rue, h.D., F.-R.S., Balfour Stewart, A.M., F.R.S., Su- 

 perintendent of the Kew Observatory, and Benjamin Loewy, Esq 37 



On the Spectrum of the Great Nebula in the Sword-handle of Orion. By 

 William Huggins, F.R.A.S 39 



Further Observations on the Planet Mars. By John Phillips, M.A., LL.D., 

 F.R.S., F.G.S., Professor of Geology in the University of Oxford 42 



Notices of the Physical Aspect of the Sun. By John Phillips, M. A., LL.D., 

 F.R.S., F.G.S., Professor of Geology in the University of Oxford 46 



On a New Geometry of Space. By Julius Pliicker, For. Memb. R.S 53 



Researches on Solar Phvsics. Second Series. On the Behaviour of Sun- 

 spots with regard to Increase and Diminution. By Warren De la Rue, 

 Ph.D., F.R.S., President of the Royal Astronomical Society, Balfour 

 Stewart, A.M., F.R.S., Superintendent of the Kew Observatory, and 

 Benjamin Loewy, Esq 59 



