5o8 



THE POPULAR SCIENCE MONTHLY. 



gutta-percha, which comes down (to the 

 sea-bottom) to arouse his faculty and fulfill 

 his functions of life a gutta-percha boring 

 and eating teredo^ who has been waiting 

 for his meal since the beginning of the 

 wo.'ld." This enemy of submarine cables 

 has already made his appearance, as was 

 briefly announced in a recent number of 

 The Monthly. It is a crustacean, less 

 than a quarter of an inch in length, and 

 known as Limnoria terebrans. " One break- 

 fast which he may take," says Dr. J. H. 

 Gladstone, " may cost more than the break- 

 fast of any luxurious Roman epicure in an- 

 cient times, because he may destroy a whole 

 cable, and it may take a year to repair the 

 damage which he may do in a minute." 



Hawksbaw on tlie Channel Tunnel. In 



the course of the debate which followed the 

 reading of a paper on the proposed tunnel 

 between England and France, at the Bris- 

 tol meeting of the British Association, Sir 

 John Hawkshaw made a speech, in which 

 he expressed his perfect confidence in the 

 ultimate success of that great undertaking. 

 " The question arises," said he, " as to the 

 risk in tuimeling through the chalk. Of 

 course we cannot measure that risk with 

 any certainty, but we are constantly in the 

 habit of undertaking engineering work 

 which sometimes involves an unknown 

 amount of risk, and it becomes the busi- 

 ness of the engineer to encounter these 

 risks. Prof. Ilebert seems to expect that 

 the chalk, although it may be continuous, 

 as we have ascertained it to be, all across 

 the channel, may have such fissures in it 

 that, in constructing the tunnel at the depth 

 we propose to go, it is possible we may cut 

 through the chalk into the green sand. 

 Suppose that were so, it would not deter 

 me from encountering this work. A great 

 mistake is often made with reference to 

 the percolation of water. Water, though 

 it passes through sand, passes with very 

 slow velocity. I have had to make deep 

 excavations in sand fifty or sixty feet below 

 the level of the sea, and though water comes 

 rather rapidly at first, until it has drawn 

 away a portion of the water which is in the 

 sand adjacent to your work, yet, after that, 

 it comes with extreme slowness. There- 

 fore, I am not afraid of percolation of water 



in that sense. With regard to the percola- 

 tion of water through the solid chalk, that 

 is of no consequence ; water passes so 

 slowly through chalk, that it might con- 

 tinue to pass, and nobody would care about 

 it. Of course there is a thing that might 

 occur which would be serious. If you 

 could imagine a clear, open fissure from 

 the bottom of the sea to the tunnel, where 

 water could pass, there is no doubt, with 

 that enormous pressure, it would pass with 

 very great velocity, and would be a very 

 troublesome thing to encounter. I do not 

 myself believe in there being any such fis- 

 sure. That is almost the only difficulty 

 which, i think, would hinder this tunnel. 

 I do not mean to say that would stop it, 

 but it is possible, if we met with a thing 

 like that, we should have to have recourse 

 to something else, which I have not yet de- 

 vised, because I do not expect it." 



Sanitary Condition of WateriKg-PIaces. 



At the Baltimore meeting of the Amer- 

 ican Public Health Association, Prof. Henry 

 Hartshorne read a report on the sanitary 

 condition of our popular watering-places. 

 The report points out the danger to health 

 at such resorts from the contamination of 

 drinking-water by soil saturated with sew- 

 age. To prevent this, one or both of two 

 measures must be adopted, namely 1. To 

 use for cooking and drinking either rain- 

 water or water conveyed from a distant, 

 uncontaminated source ; or, 2. To protect 

 the soil from contamination by the construc- 

 tion of impervious wells for receiving all 

 impure matters. The former of these meas- 

 ures is always safest; for the latter to be 

 carried out without injury to health requires 

 close and constant supervision. The report 

 finally expresses a desire that records of 

 disease and mortuary statistics of the water- 

 ing-places in the United States be collected 

 at some central point 



Geology at the Syracuse Cniversity. 



The elementary instruction in geology at 

 Syracuse University, which heretofore has 

 been distributed through the first and sec- 

 ond terms of the collegiate year, will be 

 given this year during February and March, 

 so as to occupy the attention of the stu- 

 dents with this subject almost exclusively 



