MARINE LIGHTING EQUIPMENT OF THE PANAMA CANAL. 119 



It is also to be noted that the dissolved acetylene buoy has a 375-milliineter 

 lense against a 200-millimeter lense on the Pintsch buoy. In other words, if the 

 Pintsch mantle of 30 candle-power were placed in the larger lantern, it would throw 

 a beam stronger than the 40 candle-power acetylene flame, due to its higher 

 intensity, or smaller area of projection. The range of the Pintsch mantle buoy 

 referred to, with a 15-foot focal plane, runs from seven to ten miles. 



We would also state that Gedney Channel has 12 Pintsch buoys flashing 15 

 seconds light and 5 seconds dark. 



As to Delaware River, there are 10 Pintsch buoys and i compressed acetylene. 



We note on page 1 03 , under the heading ' ' The Porous Mass — The Safety Device, ' ' 

 the statement that it is impossible to produce an explosion. We know that this 

 is the theory, but the facts, we beUeve, absolutely controvert this, as the records 

 show that in the last few years a large number of explosions have actually occurred 

 where gas has been put in receivers of this character. The record of such explo- 

 sions is altogether too long to embody in these comments, but, considering the total 

 number of flasks in the entire country charged with acetylene, the percentage is 

 low and does not by any means discredit the use of this system of lighting. 



We would also call your attention to the recent experiments at Stockholm, 

 in which Engineer Dalen, the patentee of the system, was quite seriously injured and 

 two of his assistants were also injured. We, therefore, think that the writer must 

 necessarily modify his statement that it is impossible to produce an explosion. 



Referring to the question of buoy construction and capacity, the Pintsch buoy, 

 acting under its own gas, makes it possible to combine a large capacity, maximum 

 strength and minimum weight. The minimum thickness of plates in this buoy 

 is J inch, which makes the shell self-supporting and of sufficient strength to with- 

 stand the shock of colUsions with passing vessels or floating ice. The float chambers 

 of other type buoys must necessarily be made light, never over |-inch for the 

 largest buoys, and are only subjected to a test pressure of 15 pounds to safeguard 

 against leaks. 



The following is a comparison of weights and gas capacities of various type 

 buoys : — 



12,000 lbs 8,000 cubic feet. 



Generator buoy 

 Willson No. 8|B 



Pintsch B-III 6,860 lbs 2,120 cubic feet. 



A. G. A. (Panama Buoy) 10,500 lbs 720 cubic feet. 



The buoy bodies in the case of the Willson and A. G. A. buoys are of about 

 the same weight, 10,000 pounds, but where the Willson buoy holds 2,000 pounds of 

 carbide, producing 8,000 cubic feet of gas, the A. G. A. buoy holds four 50-liter 

 flasks, a total weight of 900 pounds, and a capacity of only 720 cubic feet of gas. 

 Pintsch buoys are not painted on the inside, as the gas, being made from oil, itself 

 acts as a preservative. Buoys fifteen to twenty years old still show the mill scale 

 on the inside intact. 



