284 



NA TURE 



[July 19, 1900 



A heavy train of dining and sleeping carriages, with two 

 engines, conveying one of the crowned heads of Europe and 

 suite, arrived at the exit of Pracchia Tunnel with both engine- 

 men and both firemen insensible ; and in other cases passengers 

 have been seriously affected. 



Owing to the height of the mountain no shafts are available ; 

 but Signor Saccardo places a ventilating fan near the mouth of 

 the tunnel, and blows air into it through the annular space 

 which exists between the arch of the tunnel and the gauge of 

 maximum construction (Fig. 6). The results are remarkable ; 

 the volumes of air thrown into the tunnel per minute being as 

 follows : — 



cub. ft. 



Direct from the fan 161,860 



Induced draught through open tunnel mouth 48,140 



Total 210,000 



Or 100 cubic metres per second. 



The temperature of the tunnel air before the fan was started 

 was 107° F., with 97 per cent, of moisture, whereas, after the 

 fan had been running a few minutes the temperature was 81° F., 

 or a lowering of 26" F., and the tunnel was cool and free from 

 smoke and vapour. 



Fiiji. 6. 



The Saccardo System ot Ventilating Tdnnels. 



One can travel through with both windows open and feel no 

 inconvenience, the only remark of the brakesman riding on the 

 top of the waggons and carriages being that he finds it almost 

 too cold. 



This application is without doubt the solution of the difficult 

 problem of tunnel ventilation under high mountains, and else- 

 where where shafts are not available, and where electric traction 

 is not applicable. 



This system has within the last twelve months been brought 

 into operation on the St. Gothard, with the most satisfactory 

 results. Careful experiments are being made, but there is no 

 doubt that the problem has been solved. 



In addition to these tunnels, the Saccardo system has been 

 applied to the Giovi Tunnel near Genoa — 3300 metres in 

 length — and is being installed on the Giovi Tunnel on the 

 Genoa-Ronco Railway, 8303 m.etres in length, besides on some 

 seven other tunnels in Italy ; and plans are being prepared for 

 the Mont Cenis. 



The Simplon Tunnel. 



This tunnel is now in rapid course of construction, the 

 total length of gallery driven up to the end of April being as 

 follows : — 



yards 

 . 3228 

 • 2350 



Or over three miles in little more than eighteen months, in- 

 cluding the necessarily slow progress at the commencement. 



The total distance between the two portals will be 21,564 

 yards, or 12 26 miles. A gallery of direction has been driven 

 at both ends until the actual tunnels are reached, so as to form 



On the north or Brigue side of the Alps 

 On the south or Iselle 



NO. 1603, VOL. 62] 



a directly straight line for the accurate alignment of the work 

 from end to end. 



This great undertaking will consist of two single-line tunnels 

 running parallel one to the other, at a distance apart from centre 

 to centre of 55 feet 9 inches ; and one of the chief features is the 

 much lower altitude of the rails above sea-level than any of the 

 other Alpine tunnels. This altitude is at its highest point 2314 

 feet, being 1474 feet lower level than that of the St. Gothard, 

 1934 feet lower than that of the Mont Cenis, and 1986 feet than 

 that of the Arlberg. This is a matter of great importance in the 

 question of haulage of all the traffic. 



The tunnel enters the mountain at the present level of the 

 railway at Brigue, so that no costly approaches are requisite on 

 this side. 



Admirable arrangements have been made for the welfare of 

 the men, to avoid the heavy death-rate which occurred on the 

 St. Gothard, and it may be interesting to state what some of. 

 these are. For every cubic foot of air sent into the latter tunnel, 

 fifty times as much will be delivered into the Simplon. Special 

 arrangements are made for cooling the air by means of fine jets 

 of water and spray. 



The men on emerging from their work, wet through and 

 fatigued, are not allowed to go fiom the warm headings into the 

 cold Alpine air outside, but pass into a large building which is 

 suitably warmed, and where they change their mining clothes 

 and are provided with hot and cold douche baths. They put on 

 warm dry clothes, and can obtain excellent food at a moderate 

 cost before returning to their homes. Their wet and dirty 

 mining clothes are taken charge of by appointed custodians, who 

 dry and clean them ready for the morrow's work. These and 

 other precautions are expected to reduce the death-rate to a very 

 great extent. 



With a view to the rapid advancement of the work, the late 

 M. Brandt, whose death is greatly to be deplored, devised after 

 liis long experience on the St. Gothard his now well-known 

 drill. As details of this have been published, and as they would 

 lie too technical for this evening's discourse, it will only be 

 necessary to refer to them briefly. This drill is non- percussive, 

 nor is it armed with diamond. It is a rotatory drill 3 inches in 

 diameter with a pressure on the cutting points of 10 tons moving 

 at slow speed, but capable of being acclerated at pleasure, and 

 of being rapidly withdrawn. 



The progress of each of the two faces during the month of 

 April last has averaged 17 feet 34 inches per day, and is a 

 remarkable corroboration of the speed estimated by the 

 i-ngineers four years ago. The estimate was as follows : — 



I at year, the daily progress at each face would be ... 8 '85 feet 



2nd ,, ,, ,, ,, ,, ... 17-22 ,, 



3rd ,, ,, ,, ,, ,, ... 19-18 ,, 



4th „ „ ,, „ ,, ... 21-32 „ 



5ih „ ,, „ ,, „ ... 3I-X6 „ 



The work is now in its second year, so that the estimated 

 speed is being exceeded. In other words, the tunnel is being 

 driven through granite at a higher speed than is attained in 

 London clay. 



It was at one time intended to sink a 20-inch bore-hole from 

 the village of Berisal to the tunnel, a depth of some 2400 feet, 

 for the purpose of delivering water at high-pressure for the 

 works. This may still be done, but the meandering of the tool 

 might result in the awkward dilemma of having to search for it, 

 in solid rock, below ground. 



The probable cost of the work now in hand will be about 

 2,000,000/., and the time occupied in completing the tunnel 

 ready for traffic is estimated to be S| years, a penalty or a 

 bonus, as the case may be, for delay or acceleration being fixed 

 at 200/. a day. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



0.\FORD. — The following is the text df the speech with which 

 Prof. J. Mark Baldwin, professor of psychology in Princeton 

 University, was presented for the degree of D.Sc. honoris causa. 

 This is the first time the degree has been conferred in Oxford, 

 it having been created only quite recently. The speech was 

 written by Mr. A. C. Clark, of Queen's College, and Prof. 

 Baldwin was presented by Prof. E. B. Elliot, F.R.S., in the 

 absence of Prof. Love, F.R.S., who would in the ordinary 



