December. IQIO. 



KNOWLEDGE. 



489 



through the primary, forming a high frequency oscillatory 

 circuit, and the secondary of the spark coil transmits this 

 energy- to the X-ray tube, or aerial. It is claimed that this 

 method of obtaining a high tension discharge has many 

 advantages, renderin.g it specially suitable for wireless 

 telegraphy as well as X-ray work. 



TECHNICAL OPTICS.— The London County Council 

 Education Department have circularized members of the 

 optical trade in London, asking them to state their views as 

 to the need for an Opto-technical Institute in London, and to 

 indicate what advantages they would expect to obtain for 

 themselves and their employes from any facilities that might 

 be provided : also whether in their opinion the expenditure of 

 ;f30,000 for a building would be justified. The proposed new 

 institution would accommodate three hundred to four hundred 

 students, and day and e\ening classes in all branches of 

 optics would be provided. It seems probable that a 

 satisfactory answer may be given, and that British optical 

 work, which is making great efforts to regain the position 

 rightfully belonging to the country of Newton and Dollond. 

 may be greatly benefited by the establishment of such a 

 technical training school. 



SEISMOLOGY. 



By Charles D.wisox. Sc.D.. F.G.S. 



THE MESSINA EARTHQUAKE.— A summary of two 

 preliminary reports on this destructive earthquake was given 

 in "Knowledge" for last February. Since then several 

 valuable memoirs have been published. Dr. Mario Baratta's 

 final report is one of the most noteworthy. He agrees with 

 other seismologists in assigning a submarine origin to the 

 earthquake, but points out that there were two distinct foci, 

 both under the Straits of Messina ; one at their northern 

 entrance, the other farther south, near Reggio. Dr. Baratta 

 shows also that the northern focus was that in which the 

 second great earthquake of February 5th, 1783, with its 

 accompanying sea waves, originated, while the sea waves 

 which followed the recent earthquake proceeded from the 

 southern, or Reggio. focus. 



The Royal Commission appointed by the ItaUan Govern- 

 ment has also issued a valuable report. The chief object of 

 the commission was to determine the exact sites on which the 

 ruined towns should be re-built, if re-built at all. It is now- 

 well known that earthquakes are most destructive to houses 

 built on soft earthy ground, especially on sloping ground, while 

 they cause comparatively little injury to those built on hard 

 compact rock. Notwithstanding the objectionable nature of 

 the soil round Messina and Reggio, these two towns are to be 

 re-built on their original sites. The presence of the harbours 

 renders this compromise necessary, but no permanent 

 dwelling houses will be allowed on loose sloping ground, or 

 within about one hundred jards of the shore. In other 

 districts, the sites of many villages will be wholly or partially 

 abandoned. 



DESTRLCTIVENESS OF CALABRIAN EARTH- 

 yU.\KES. — Professor G. Mercalli has compiled a list of 

 destructive earthquakes which have visited the provinces 

 of the Basilicata and the two Calabrias since the beginning of 

 the sixteenth century. The total number of such earthquakes 

 is thirty-eight, and the number of deaths due to them in these 

 provinces alone is not less than 76.000. This figure is given on 

 the supposition that during the Messina earthquake 17,815 

 persons were killed at Reggio, or about 24 per cent, of the 

 population. Much higher death-rates were, however, attained 

 in other earthquakes, the highest known being 77 per cent, at 

 Terranova, in the Calabrian earthquake of 17S3: 71 per cent, 

 at Montemurro and 50 per cent, at Saponara, in the Neapolitan 

 earthquake of 1857; and 47 per cent, at .-Mtilia in the Calabrian 

 earthquake of 1638. Professor MercaUi attributes the relatively 

 high death-rates in towns to the loftiness of the buildings, the 

 crowding in individual houses, and the narrowness of the 



streets in the older parts of the to^vns. Destructive earth- 

 quakes, he notices, occur in groups, during which the 

 earthquakes take place at short intervals apart, but always with 

 a sensible displacement of the focus, and therefore of the area 

 of damage. There is also a migration of activity from 

 province to province. In the seventeenth and eighteenth 

 centuries, central and southern Calabria were most affected, 

 in the nineteenth century, Calabria Citra and the BasiUcata, 

 while in the present century, southern Calabria again furnished 

 most of the victims. 



EARTHQUAKES IN GREECE.— In the last volume of the 

 AtiiiaUs of the National Observatorv- of .Athens, Professor D. 

 Eginitis describes the earthquakes recorded in Greece during 

 the five years 1904-190S. He considers that this period was 

 one of comparative seismic calm, for the average number felt 

 w-as only one hundred and fifty-eight, while in the preceding five- 

 year periods it was five hundred and thirty-one and three 

 hundred and twenty-one. In the year 1907, only seventy-three 

 shocks were observed, and they were all of slight or moderate 

 intensity, none of them being strong enough to cause damage 

 to buildings. After the close of 1908. that is, aftertheoccurrence 

 of the Messina earthquake, the shocks, however, show a distinct 

 increase both in frequency and intensity. -As usual, the local 

 earthquakes were more often felt in Zante than elsewhere 

 one hundred and forty-two out of six hundred and twenty such 

 shocks having originated under or near this island. 



ZOOLOGY. 



By Professor J. Arthlr Thomson. M.A. 



WERE DINOSAURS VEGETARIAN ?— It has been 

 verv generally supposed that the great Sauropod Dinosaurs 

 were purely herbivorous animals, which fed on the algae and 

 other aquatic plants in the streams and marshes beside which 

 thev lived. The small, rake-like, imperfectly-rooted teeth 

 with which the front of the jaw alone was supplied, were not 

 adapted for cutting or grinding, but may very- well have 

 served for gathering in masses of floating vegetation, which, 

 it is assumed, were pressed free of water in the arched palate, 

 and swallowed without mastication. The pebbles, presumably 

 gastroliths, found along with the remains give support to this 

 view. 



Tomier, however, recently suggested that the small size of 

 the abdominal ca\-ity relative to the bulk of the animal points 

 to a more nutritious diet than aquatic vegetation. The ladle- 

 like formation of the lower jaw, and the broad, flat muzzle 

 seem to him to indicate that small, soft aquatic animals 

 formed at least part of the food. 



Now Dr. Versluys puts forvvard the interesting theorv- that 

 these giant reptiles were fish-eaters, and many details of their 

 structure appear more intelligible on this theory than on any 

 other. The upper jaw in some forms, e.g.. Diplodocus, was 

 apparently movable, and this would enable the animal to 

 open its mouth quickly and snap at a passing fish, which 

 would be swallowed whole. The long, muscular, and extremely 

 mobile neck, the small head, the mobile jaws, and the trap- 

 like teeth must have combined to make a verj- formidable 

 fishing apparatus, which could be used with good effect even 

 against considerable resistance, as under water. It is also 

 suggested that Diplodocus may have used its long whip-like 

 tail to lash the water, and thus bewilder its intended prey. 



INHERITANCE OF "ACQUIRED CHARACTE;RS."— 

 Dr. F. B. Sumner in the course of his researches on white mice 

 has carried out a series of experiments which are of great 

 interest. He reared one set of mice in a warm room (about 

 21-C), and another set in a cold room (about 5°C), to 

 determine the effects of the difference of temperature on their 

 growth. He found that the mean length of tail, foot and ear 

 was greater in the w^arm-room mice than in the cold-room 

 mice. The next point to be determined was whether and to 

 what extent these somatic modifications reappeared in the 

 offspring. The experimenter reared one hundred and forty- 



