348 



scie:nce. 



[Vol. Vin., No. 193 



mass simply, but to the duration of the commodity, 

 to the time elapsing while it is being consuTned. 



The theory of varying degrees of utility seems to 

 have its origin in the fact, that, assuming the provi- 

 dent trait to be perfectly developed, the intensity of 

 our desires of a prospective nature varies with our 

 estimate of probable utility, the probability decreas- 

 ing as the length of time estimated to ensue before 

 the anticipated satisfaction increases ; Jevons's chap- 

 ter on the ' Theory of utihty,' with the necessary 

 changes in phraseology, would furnish an excellent 

 discussion on the subject of desires of a prospective 

 nature, which do have two dimensions, — one the 

 estimated intensity of the anticipated satisfaction, 

 the other its probability as affected by the length of 

 time to elapse before its estimated occurrence. 



But when we enter upon discussion as to the sources 

 of desires, and how desires may be modified, we must 

 say, with Pascal, " C'est un cercle infini, dont le 

 centre est partout la circonference nulle part." 



A. E. Rogers. 

 Orono, Me., Oct. 5. 



Earthquake sounds. 



Does any one attempt to offer an explanation for the 

 sound that preceded and accompanied the late earth- 

 quake, or earthquakes in general, where the sounds 

 are noticeable ? I supposed it was presumable that 

 they were due to the commotion in the earth's crust 

 caused by the radiating waves. But how can that 

 be, when the earth-waves move six to eight times 

 faster than sound-waves ? If that be so, would it not 

 appear as if the sound-waves ought in part to come 

 up after the shock has passed ? I was asleep when 

 the first and heaviest shock first reached this place 

 (six miles west of Greensborough. in Guilford county), 

 so I cannot tell to what extent the sound preceded 

 the shock. There were two subsequent shocks which 

 were preceded by low roaring and rumbling, so that 

 we predicted the coming of the earth-waves. I said 

 to my wife, ' Now we v.-ill have another shake ; ' and 

 we waited probably three seconds after I had spoken, 

 when the house began to rock. I do not expect you 

 to write me personally, as you will not likely have 

 time, but, if my question should be worthy of note, 

 perhaps some of the geologists of your company could 

 give us a line through Science. Joseph Moore. 



New Garden, N.C., Oct. 6. 



Unexplained noises. 



Your comment on mysterious noises in Science for 

 Oct. 1 recalls to my memory a very remarkable in- 

 stance of the transmission of sound and motion. 



On the 14th of February, 1862, I was working with 

 my father in his sugar orchard ten miles west of 

 Madison, Ind., and five miles north of the Ohio River. 

 During the entire morning, which was warm, cloudy, 

 and calm, we heard most distinctly the discharges of 

 heavy artillery. The reports would often follow in 

 quick succession. I, as most lads would have been 

 in similar circumstances, became thoroughly alarmed. 

 I felt quite sure that the whole confederate army was 

 close upon us, since the source of the cannonading 

 seemed to be no farther south than the river, 



I finally prevailed upon my father to go home, 

 where we found the inmates of the house greatly 

 alarmed at the noises and the rattling of the windows. 

 The shocks, as I remember them, were much like the 

 slight earthquake disturbances experienced lately in 



different parts of the country. For several miles 

 along the river these noises were heard and the shocks 

 felt. Nevertheless the day passed, and no invading 

 foe appeared. The morrow brought the news of the 

 bombardment of Fort Donelson. 



When it is remembered that Fort Donelson is more 

 than two hundred miles from the locality just de- 

 scribed, it is certain that these concussions could 

 not have been carried through the air. 



I have been told that the limestone formation com- 

 ing to the surface along the right bank of the river 

 in Jefferson county, Ind., is the same as that on 

 which Fort Donelson rests. The cannonading which 

 was heard so distinctly that day by hundreds of 

 people in Indiana occurred at Fort Donelson, and the 

 sound-waves were conveyed entirely across Ken- 

 tucky, and probably at a considerable depth below 

 the surface, by a continuous ledge of limestone. I 

 have thought the phenomena above described worthy 

 of record in your columns. H. W. Wiley. 



Fort Scott, Kan., Oct. 8. 



How astronomers may work. 



In your editorial of Sept. 24, referring to Professor 

 Pickering's plan for making the Harvard college ob- 

 servatory useful to all other observatories, and to 

 astronomers all over the world, you also notice apian 

 of my own, which I formulate as follows : — 



" We mean to put the large telescope (of the Lick 

 observatory) at the disposition of the world by invit- 

 ing its most distinguished astronomers to visit us one 

 at a time, and by giving to them the use of the in- 

 strument during certain specific hours of the twenty- 

 four. In this way we hope to make the gift of Mr. 

 Lick one which is truly a gift to science, and not 

 merely one to California and to its university." 



Your comment on this plan is that you suspect that 

 Professor Holden ' was hard-pressed to devise it.' 



I trust that your impression will not be shared by 

 Professor Young, if he remembers the discomforts of 

 his expedition to Sherman ; or by Professor Langley, 

 if he recalls the hardships of his own to Mount Whit- 

 ney ; or by Dr. Huggins, when he recollects the 

 hundreds of failures which have come in his delicate 

 researches in spectroscopy and photography from the 

 London climate : or by Mr. Burnham, when he re- 

 members how many of the double stars which he dis- 

 covered at Mount Hamilton with a six-inch telescope 

 were ' difiicult ' in Chicago with one of eighteen 

 inches. Not to mention any other names, I am sure 

 that these astronomers will feel a sense of gratitude 

 when the facilities of the Lick observatory and the 

 opportunities of its climate are put at their disposition, 

 and will attribute the offer to a generous desire to 

 forward science, and not to a scheme to eke out a 

 scanty mcome. As a matter of fact, I have directed 

 the policy of the observatory since 1874, and it is a 

 pleasure to me to be able in 1886 to announce a plan 

 which has been constantly in my thoughts for more 

 than ten years, and which seems to me to be a long 

 step in the true direction. I trust it will also seem 

 to be such to my fellow-astronomers. It would have 

 been natural to have looked for the same view from 

 the editor of Science ; but, as long as the plan com- 

 mands their respect and my own, it will be carried 

 out. You will have to look to its results to see if it 

 may not eventually command your own also. 



Edward S. Holden. 

 Berkeley, Cal., Oct. 2, 



