April 23, 1903] 



NA TURE 



589 



most interesting piece of apparatus was a three-phase 

 motor carried on a suspended bed, so that the torque 

 could be measured, and driving a dynamo coupled 

 direct to the end of the shaft. The other end of the 

 motor spindle was fitted with a disc divided into black 

 and white sectors, so that the slip of the rotor when 

 driving the dynamo at various loads could be directly 

 observed by the stroboscopic effect produced on illumin- 

 ating the disc with an incandescent lamp on the mains 

 supplying the current. There are also two other 

 small motor generators, and a motor of about three 

 horse-power fitted with an electromagnetic brake disc. 

 The photometry room contains a Lummer Brodhun 

 photometer with Hefner Alteneck standard for general 

 photometric work. For variations of light ,in arc 

 lamps, as shown by the illumination in a plane, a 

 photometer due to Prof. Rousseau is used. This con- 

 sists of a vertical disc with two radial arms carrying 

 mirrors. The arc is placed in the axis on one side of 

 the disc, and the light is reflected by the mirrors on to 

 the other side, where it gives two shadows of an axial 

 rod. One of the arms and the mirror on it being con- 

 veniently clamped, the other arm is moved from point 

 to point, and the mirror on it is adjusted until the 

 shadows are equally intense as in a Rumford photo- 

 meter. The variation of the light is thus found in 

 terms of the fixed direction, and the absolute value of 



YfffYYYTnTYT 



1 



Hours 



Fig. r. — Graphic record of cement test. 



this is found, if desired, by means of a Weber photo- 

 meter. 



The engineering laboratories contain a small experi- 

 mental steam engine and other plant, including a 

 dynamo driven by a high speed steam engine, a gas 

 engine and pumps. Complete efficiency tests are 

 carried out, of which the students are required to write 

 detailed reports. There is also a ioo ton testing 

 machine. This is worked hydraulically, the town 

 water being received at three atmospheres and trans- 

 formed to 250 atmospheres. There is also a fine 

 adjustment worked electrically, the forward or reverse 

 motion being put on by an electromagnetic coupling. 



At the time of the visit tests were being made on the 

 deflection of cement beams used for arching in floor 

 work. They were being loaded up to the point of 

 fracture. 



One of the most interesting pieces of apparatus was 

 that used for testing the setting qualities of Portland 

 cement. For testing, the cement is made up in a 

 mould about 3 inches in diameter and ij inches thick. 

 This is rotated slowly about its axis by clockwork, 

 which allows a needle weighted with 300 grammes to 

 fall once every quarter of an hour. If the cement is 

 soft, it pierces' the cement to the bottom, but as harden- 

 ing sets in the needle does not pierce the full thickness, 

 until finally it fails to make any impression. The re- 

 sult is automatically recorded as shown in the figure 

 (Fig. 1), in which the ordinates represent travel of the 

 needle, and abscissa? time. It will be noticed that the 



NO. I 747, VOL. 67] 



effect of hardening in this example appeared after 

 about 4 hours, and the needle failed to make an im- 

 pression after 55 hours. 



The Italian visit made it evident that not only was 

 beautiful scenery to be enjoyed, but that Italy is at 

 present the home of some of the most interesting and 

 original engineering works. 



NOTES. 

 The Royal Society's Croonian lecture will be delivered 

 on Thursday, April 30, by Prof. Klement A. Timirjazev, 

 upon " The Cosmical Function of the Green Plant." 



A correspondent informs us that on April 1 Dr. G. V. 

 Neumayer left the Deutsche Seewarte at Hamburg, of which 

 he had been director since 1876. 



A Reuter message from St. Petersburg announces that 

 the Imperial Russian Geographical Society will send a 

 scientific expedition into Mesopotamia during the year. The 

 expedition will be under the leadership of M. Kaznakoff, and 

 will include among its members M. Alferaki, zoologist, and 

 M. Tolmatcheff, geologist. 



The President of the Board of Agriculture has appointed 

 a Departmental Committee to investigate experimentally 

 and to inquire into and report upon : — (1) The composition 

 and essential constituents of efficient dips and other prepar- 

 ations for the treatment and dressing of sheep, and their 

 effect upon the animal treated or dressed, and upon the 

 parasites and other organisms for the destruction of which 

 they are used ; (2) the methods in which such dips and other 

 preparations should be employed, and the appliances and 

 facilities requisite for the purpose ; (3) the times and intervals 

 at which sheep should be treated or dressed, regard being 

 had (a) to the life-history and characteristics of the sheep- 

 scab Acarus and of the other parasites and organisms of 

 sheep which require external treatment, and (b) to the 

 practical conditions under which sheep-farming is carried on 

 in various parts of the United Kingdom. The committee 

 includes Dr. T. E. Thorpe, C.B., F.R.S., Prof. J. R. Camp- 

 bell, Mr. A. C. Cope, Mr. M. Hedley, and Dr. W. Somer- 

 ville. Prof. Winter will act as secretary to the committee. 



Mr. W. de Fonvielle writes to say that for the first time 

 since the Eiffel Tower was open to the public in 1889, it was 

 used for astronomical purposes on the occasion of the recent 

 lunar eclipse (April 11-12), when a number of members of 

 the Society astronomique de France spent some hours 

 making observations on the terrace of the monument at an 

 altitude of about 870 feet above the beine. 



A Reuter telegram from Colon states that slight shocks 

 of earthquake occurred there and at Panama on the morn- 

 ing of April 17. 



The Athenaeum announces the death, in his seventy-third 

 year, of Prof. Laborde, of the Paris School of Anthropology, 

 and of M. E. Duporcq, the secretary of the French Mathe- 

 matical Society, at the early age of thirty-one. 



A general agreement has been arrived at between 

 Marconi's Wireless Telegraph Company and a group of 

 Danish financiers in Copenhagen for the establishment 

 of a wireless system between Iceland and the north of 

 Scotland. 



The following announcement appeared in Saturday's 

 Times (April 18) : — " Owing to the breakdown of a sub- 

 sidiary device employed in connection with one of the tele- 

 graph stations established by the Marconi Company for 



