SCIENCE. 



[Voi. XXill i\o. 570 



powerful fog-signal in operation at Point Juditli could 

 not be heard. That area was soon marked by a whistling 

 buoy. A similar area was found and plotted five miles 

 from Block Island, and a whistling buoy was placed in the 

 centre of that silent spot. 



A curious state of things was found off the light house 

 on Little Brewster Island, Boston Harbor. Complaint 

 had been made as to the action of the fog-signal there, 

 which was a DaboU trumpet, and another and better fog- 

 signal was wanted. Some asked for a siren, some for a 

 steam whistle, and some for a larger and better Daboll. 

 So a battery of fog-signals, one of each kind, was 

 placed there, and I was aj)pointed, with others, on 

 an informal sort of a board to ascertain and re- 

 23ort which of the three was best adap)ted to the 

 jslace. It was found that the siren gave the best ef- 

 fect, and it was duly established there, and is there yet. 

 But it was also found that there were several areas of 

 silence within normal ear-shot of that fog-signal which 

 were constant as to their general position, but which were 

 floating or variable in their actual positions. There were 

 already so many lights, buoys, spindles, etc., in that 

 vicinity it was recommended that no more be established 

 there lest it cause confusion. It was deemed the most 

 curious concatenation of peculiar phenomena yet met. 



In observing all these peculiar phases of non-audition 

 of fog-signals at points where they should be heard, only 

 one vessel had been used at a time. Hence, we had no 

 record as to the sound at more than one place at a time, 

 of a fog-signal. It had been a favorite plan of Professor 

 Henry to use several vessels simultaneously about the 

 same fog-signal, so as to learn where its sound was heard, 

 as well as where it was not heard, at the same moment. 

 The board decided to follow that plan this fall and in this 

 way to re examine, with several vessels at the same time, 

 the sound of the fog signal, which had heretofore been 

 examined with but one vessel at a time. 



This duty was devolved on me, and I was ordered to 

 the Clover, a fast-sailing schooner, to carry it into effect. 

 I was permitted to invite two members of this society, 

 Prof. C. A. "White, LL. D., Member National Academy of 

 Sciences, and Prof. H. A. Hazen, Forecaster of the Weath- 

 er Bureau, to go with me on this cruise, and the invita- 

 tion was afterwards formally repeated by the board. It 

 was i^lanned that when I had reached a scene of opera- 

 tion and a prop)er day was found, I was to impress 

 any other light house vessel within reach for that day, 

 and the'light house district officers were directed to give 

 every practical aid to the expedition. This they did with 

 great readiness and good effect. 



Thus it has happened that observations have been made 

 recently from three vessels simultaneously, at three dif- 

 ferent places, of the sound of a number of fog-signals at 

 which abnormal phenomena had been observed and re- 

 p)orted before; and the recent observations have been 

 made, and ha've been plotted on the same scale as previous 

 observations; so that all the observations made at each 

 place whether in 1881, 1885 or 1893 are now comparable. 



The methods used at Little Gull light house and fog- 

 signal station, for instance, were as follows: 



The Clover arrived at New London Harbor on the 

 morning of Oct. 19. Leaving her trying to work up to 

 the citj', against a headwind, I went ahead in the steam 

 launch. At the light house depot I found the light house 

 steamer. Cactus, with banked fires. In half an hour she 

 was under way, and towing the Clover toward Little Gull 

 light station. Dr. White, Professor Hazen and I went on 

 shore and the light keeper was directed to start up his 

 fog-signal. Dr. White remained on the islet to see that 

 the orders were carried out and to note any variations 

 made from any cause in the usual sound. Then Profes- 



sor Hazen went on board of the Clover and I returned to 

 the Cactus, and each vessel ran over i^rescribed courses. 

 Observations of the intensity of the sound were made on 

 each vessel each minute. The direction and force of the 

 wind, the temperature by wet and dry bulb thermometer, 

 and the pressure of the atmosphere, as shown by the bar- 

 ometer, were duly recorded. The appearance of the sea 

 and the sky were also noted. 



The next day the Cactus was engaged on other impera- 

 tive duty and the Clover went out from New London 

 Harbor, where we had spient the night, without her. But 

 Professor Hazen made a rather adventurous cruise in an 

 open steam launch about the fog-signal, with excellent 

 results. 



On the third day Professor Hazen was on the schooner 

 Clover, and I was on the steamer Cactus. Dr. White was 

 landed on Great Gull Island, which is small, treeless, and 

 uninhabited, where he had large opportunity, which he 

 fully used, to get the sound of the fog-signal under cir- 

 cumstances not had before. Here Dr. White noted the 

 action and the result of peculiar echoes, and his studies 

 of these echoes have developed an important factor in the 

 discussion. 



Off Point Judith we had very light wind, almost no sea, 

 though there was a heavy swell rolling in, and a fair sky; 

 in other words, we had an excellent day for hearing. 



The Cactus being again with us, I went on her, Dr. 

 White stayed with the Clover, and Professor Hazen, in spite 

 of the bad character of that vicinity for quick and severe 

 changes of weather, again took to the steam launch; so we 

 got simultaneous observations of the sound of the fog- 

 signal at Point Judith from three vessels, each cruising 

 about on different lines. 



In our work about the light on Little Brewster Island, 

 at the entrance to Boston Bay, which occupied two days, 

 we had the help of two other steamers. Major Livermore, 

 of the Corps of Engineers, U. S. A., and Engineer of the 

 First and Second Light House Districts, went with us on 

 his steam propeller, the Myrtle, and Lieutenant Com- 

 mander Colby, U. S. N., assistant to the Inspector of the 

 Second Light House District, accompanied us on the side- 

 wheel steamer. Geranium. On the first day I was with 

 Major Livermore on the Myrtle, Dr. White was in charge 

 of the work on the Clover, and Professor Hazen went with 

 Lieutenant Commander Colby on the Geranium. On the 

 second day Dr. White went with Major Livermore; I 

 stayed on the Clover, and Professor Hazen remained with 

 Lieutenant Commander Colby on the Gei'anium. Each 

 vessel ran on different courses on different days, and we 

 got many simultaneous observations from the three ves- 

 sels. Most of the time was spent on the open ocean be- 

 tween Boston light and Minot's Ledge light, or beyond, 

 or between Boston light and Egg Eock light. Part of 

 each day, as we were going and coming' from Boston Har- 

 bor, was spent in the Narrows, or in Broad Sound, at the 

 rear of the fog-signal we were observing. 



Now, as to our tools. We had on the Clover an anno- 

 meter at the foremast head, and another at the end of the 

 jib-boom. Both were connected by electric two-conduc- 

 tor cables with self -registering apparatus in the cabin. 

 We also had a barograph which registered the pressure 

 of the atmosphere, and we had a very delicate barometer 

 by which to check the barograph These had been lent 

 to the expedition by the Weather Bureau, and were under 

 the charge of Professor Hazen, who looked after our me- 

 teorology. In addition to these, the Professor had brought 

 his own sling j)schycometer, an ingenious arrangement 

 of wet and dry bulb thermometers, which he managed 

 with great skill, and clung to with much affection. The 

 Clover had her own complement of thermometers, barom- 

 eters, etc., in addition to what had come to us from the 



