Februaky 13, 1885.1 



SCIENCE. 



129 



have lost sight and hearing from the same 

 disease. The returns have not yet been suf- 

 ficientty anal} T zed to enable us even to separate 

 the congenital from the adventitious cases. 

 We cannot therefore tell at the present time 

 how far the evidences of correlation may be 

 weakened by a closer inspection of details. 



The large number of deaf-mutes who have 

 been classified as idiots, also suggests caution 

 in accepting the returns. I recently met a 

 3'oung lady — one of the brightest and best 

 pupils of the Illinois institution for the deaf 

 and dumb — who commenced her school-life 

 in an idiot-asylum. She was there discovered 

 to be simply deaf, and was transferred to the 

 Institution for the deaf and dumb at Jackson- 

 ville, where she not only received a good 

 education, but was successfully taught to 

 speak. Not only are children who are simply 

 deaf, sometimes sent to idiot-schools ; but 

 idiotic children who hear perfectly are often 

 sent to institutions for the deaf and dumb, 

 when it becomes the painful duty of the prin- 

 cipal to undeceive the parents as to the real 

 condition of their child. The difficulty in 

 distinguishing these two classes of defective 

 persons arises from the absence of articulate 

 speech. Children who are deaf from infancy, 

 and idiots, do not naturally speak, but from 

 very different causes. In the one case, the 

 cause is lack of hearing ; in the other, lack of 

 intelligence. The judgment of unskilled per- 

 sons regarding the intelligence of deaf-mutes 

 should evidently be received with caution. It 

 is only to be hoped that the number of idiotic 

 deaf-mutes returned in the census has been 

 over-estimated. Before accepting the results 

 as thoroughly reliable, it would be well to know 

 whether or not the persons who made the re- 

 turns were competent to judge in the matter. 

 Alexander Graham Bell. 



EARTHQUAKE OF JAN. 2, 1885. 



The daily papers of Jan. 3 contained re- 

 ports of a slight earthquake in Marj T land and 

 Virginia the previous evening. 



On Jan. 4 circulars of inquiry were sent to 

 more than twenty places in the vicinity of the 

 reported shock. The questions asked had 

 reference to the time of the shock, its dura- 

 tion, number of shocks, character of accom- 

 panying noise, and intensity according to a 

 given scale. It will be necessary here to quote 

 only the first three of the six numbers of this 

 proposed scale of intensity, which are as 

 follows : — 



No. 1. Very light. — Noticed by a few per- 

 sons, but not generally felt. 



No. 2. Light. — Felt by the majority of per- 

 sons, rattling windows and crockery. 



No. 3. Moderate. — Sufficient to set sus- 

 pended objects (chandeliers, etc.) swinging, 

 or to overthrow light objects. 



In response to this circular, seventeen writ- 

 ten reports, and a copy of the Leesburg Mirror, 

 were received ; and from these replies, together 

 with reports in the New-York Tribune and in 

 Science, a tabulated summary was prepared, 

 and represented graphically upon the accom- 

 panying map, on which are marked all the 

 places from which an}- report, either manu- 

 script or press, was at hand. 



As is there shown, the northern boundary 

 of the region affected is well determined by 

 manuscript reports from five places lying be- 

 yond its limits. The inquiries, which might 

 have determined its limits as clearly in other 

 directions, failed to elicit any response. It 

 appears to have extended very little, if at all, 

 west of the mountains. The only direct report 

 obtained from that region was from Boones- 

 borough, Md., where it was felt near, but not 

 in, the town. The Leesburg Mirror stated 

 generally that it was felt in Jefferson county, 

 W. Va., but no reply was received to circu- 

 lars sent there. 



The closest approximation to the true time 

 is probably 21 h. 12.1 m. eastern time, as given 

 by W. C. Winlock at Washington, D.C., with 

 which agree also the reports of W. J. Grove 

 at Lime Kiln, Md., and W. H. Routzahn at 

 Midclietown, Md. These are the only reports 

 which vary from 21 h. 10 m. or 21 h. 15m., ex- 

 cept Fairfax, Va., which is 21 h. 5 m., and 

 W. H. Dall at Washington, who gave 21 h. 

 16 m. At Adamstown, Md., two shocks were 

 reported ; and at Buckeystown, Md., a second 

 very light shock at 21 h. 45 m. 



The estimates of duration were, as usual, 

 very discordant, varying all the way from 

 three seconds to two minutes. As the ten- 

 dency of ordina^ observers is always to ex- 

 aggerate this element, the unexpected and 

 exciting nature of the phenomena making the 

 time seem longer than it really is, probably 

 ten or fifteen seconds would be a liberal esti- 

 mate of the duration. 



The noise accompairying the shock was 

 compared to that made b} r a loaded wagon 

 passing rapidly over frozen ground or over a 

 bridge, to distant thunder, and to the roaring 

 of a chimney on fire. In some cases persons 

 went out of their houses to see if their chim- 

 neys were not burning. 



