PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 493 



for the whole height from the bottom of any water valley to the summit. 

 This proposition is easily proved by trying tlie height upon a ship's mast, 

 at which the horizon is always in sight over the tops of the waves, allow- 

 ance being made for accidental inclinations of the vessel, and for her sink- 

 ing in tlie water to much below the water line at the instant when she reaches 

 the bottom of the hollow between two waves. The spray of the sea, 

 driven along by the violence of the wind, is of course much higher than 

 the summit of the liquid wave; and a wave coming against an obstacle, 

 may dash to almost any elevation above it. At the Eddystone light-house, 

 wdien a surge reaches it which has been growing under a storm all the 

 way across the Atlantic, it dashes even over the lantern at the summit." 



The Chairman. — I will remark, in relation to this subject, that Dr. Scores- 

 by, who studied this matter very thoroughly, made observations from a 

 vessel at sea during a great storm, and he found that the largest waves 

 were some twenty-five feet high and six hundred feet long. 



Dr. Stev.ens. — Several years ago I crossed the Atlantic, and one day, 

 while in the longitude of the Azores, in the midst of a violent storm, a large 

 East Indiaman, a vessel of the first class of that day, came drifting- along, 

 and lay in the trough of the sea, while wo lay in another. When the storm 

 appeared at its highest, it suddenly ceased, and I then had an opportunity 

 of observing- the motion of the East Indiaman, which at times was entirely 

 out of sig-ht, even from the main top mast of our vessel. The waves 

 stretched as far as the e3-e could reach, and it appeared to me to be the 

 same identical wave that followed us from Sandy Hook. 



Mr. Bull read a statistical account of the railroad and ferry travel of this 

 city, for the past year. After which, he presented an oil lamp to burn 

 without a chimney, of which he spoke at a previous meeting. The lamp 

 was lighted and appeared to burn as bright and free from smoke as could 

 be expected ; there was nothing new claimed for it, and it was only exhibited 

 as showing the above mentioned qualities. The burner was made by Mr. 

 Miller of 211 Centre street. 



Mr. Page. — I have some twenty-five different burners that have been got 

 up for this purpose. There has been a g-reat amount of time, labor, and 

 money lost, by persons getting- up these burners not fully understanding 

 what is essential to make a good burner. If they would acquaint them- 

 selves with the theory of combustion and the composition of the different 

 oils, the dissimilarity between petroleum and coal oil, there would be less 

 failures in this respect. There have, however, been wonders done thus far, 

 as those wdio know what the oil is can appreciate; the improvements that 

 have been made are bringing the oil into very general use, particularly on 

 steamboats- and railroads. I have experimented very largely with neax'ly 

 all the burners that have been introduced, and tested their illuminating 

 qualities with the photometer. 



At the suggestion of a member, Mr. Page said he would exhibit several 

 burners, and show the diiference in their illuminating properties, at the 

 meeting of April 9th. 



