268 



SCIENTIFIC NEWS. 



[Mar. 23, 1S88. 



ROCK EXCAVATOR. 



T-JITHERTO it has been usual to bore and then to 

 blast rock when it interferes with the carrying out of 

 engineering works, such as harbours and canals, and this 

 is effected with great difficulty and expense when, the 

 rock to be removed is under water. Our illustration on 

 the preceding page represents a new kind of rock-cutting 

 dredger, which has been built by Messrs. Lobnitz and 

 Co., of Renfrew, for deepening and widening the Suez 

 Canal, at one part of which about three million tons of 

 hard limestone are to be removed. In this system there 

 is no boring, and no blasting, the rock being broken up 

 by a succession of blows given to it by heavy vertical 

 chisel-pointed rams. In the Derochense there are ten of 

 these rams, each 42 feet long, and each weighing four 

 tons. These rams can be seen through the framing in 

 the forward part of the dredger, there being five rams on 

 each side of the well through which the dredging buckets 

 lift the debris. The rams are raised by hydraulic power 

 to a height of ten to twenty feet above the rock; they 

 are then allowed to drop, and as they can deliver about 

 500 blows in an hour, it is easy to imagine that the 

 surface of the rock must necessarily be shattered. 



The work done by this machine is very rapid, as was 

 proved in a careful trial made in December last in the 

 Western Tidal Harbour of the James Watt Dock, 

 Greenock. The rock bottom at this place is of peculiar 

 formation, very hard and difficult to operate on ; but not- 

 withstanding this the amount of solid rock cut and lilted 

 averaged over forty tons in a working hour. Our illus- 

 tration represents a general view of the Derocheusc as 

 seen at work during this trial. 



This system has the further advantage of enabling rock 

 to be removed close to dock walls, without endangering 

 their stability, whereas with blasting this is attended 

 with considerable risk. 



The same principle can be applied to the removal of 

 rock on dry land, and extensive trials were made with a 

 single ram at Craigmillar Quarrj', Edinburgh, where the 

 rock is one of the hardest in Scotland. The ram 

 v/eighed two tons, and was raised by a steam 

 winch; the fall of the ram was about eighteen feet, ar d 

 an average of over four cubic feet of rock was dislodged 

 at each blow. With a heavier ram the yield of broken 

 rock would be still greater, but the results actually 

 obtained are sufficiently good to warrant us in speaking 

 well of the system, and they must be very encouraging to 

 the makers of the machine. 



— ■^J»;^»^5<f-» — 



EARTHQUAKES AS AGENTS IN THE 

 FORMATION OF NATIONAL CHA- 

 RACTER. 



pROFESSOR MILNE, of Japan, well known as a 

 diligent inquirer into the causes, the phenomena, 

 and the results of earthquakes, has recently put forward 

 in the Transactions of t tic Japanese Siesmological Society 

 some striking speculatio.is on the possible moral and 

 emotional results of these catastrophes. He contends 

 that the human mind never grows accustomed to even 

 the smallest earlhquakes, but that a constantly-increasing 

 terror is produced. Ihe effects of the more violent con- 

 vulsions, he argues, are disastrous no less morally than 

 physically. The survivors of the great Manila earth- 

 quake in July, 1880, declaied themselves demoralised. 

 'Ihey declared: — "We have lived ten years in a 



minute " ; and the general effect of such earthquakes as 

 that of Caracas in 1812 — when "from the first tolling of 

 a bell to the falling of the last stone of the city of Caracas 

 one minute only elapsed " — of Chio in 1881, and many 

 others, is that " whole communities suddenly suffer a 

 mental paralysis which in many casesamounts to madness," 

 and "for years after such a catastrophe every tremble 

 in the earth will produce a panic. The experience and 

 fears of fathers are handed down to their children, and 

 before these terrors have become things of the past a 

 fresh disaster adds fuel to the fire consuming the moral 

 constitution." In former times earthquakes were, like 

 cyclones, regarded as Divine judgments for the sins of 

 men. In 1608 the Kirk Session of Aberdeen accepted a 

 shock as " a document that God is angry against this land, 

 and against this city in particular." On further con- 

 sideration it was decided that the special sin of the people 

 of Aberdeen was salmon-fishing on Sunday, and a certain 

 learned Fellow of the Royal Society argued in the Philo- 

 sophical Transactions that earthquakes must be Divine 

 judgments on men, seeing that they visit great cities and 

 not bare cliffs and uninhabited beaches, forgetting that 

 on uninhabited beaches the phenomena produced are un- 

 observed and unrecorded. In Lisbon in 1756 during 

 the earthquake the populace seized a young Englishman 

 and haptised him against his will to appease the wrath of 

 an offended deity. 



Professor Milne concludes that the effect of seismic 

 phenomena on the human race has been very great. In 

 some cases they have distorted the powers of reason and 

 have begotten superstition, the imagination has been 

 stimulated, and among the weaker members of the com- 

 munity, by the creation of feelings of timidity, resulting 

 perhaps in mental aberrations like madness or imbecilitj', 

 the seeds have been sown for a process of selection, by 

 which the weaker members in the ordinary course of 

 racial competition must succumb. 1 he survivors, living 

 in insecurity, perhaps grow reckless and careless, and 

 thus the whole life of a nation may be affected. The 

 successful nations of to-day are not those which have had 

 to fight against these unintelligible terrors of nature. In 

 such places as Japan and Naples we find light-hearted 

 carelessness and disregard for the morrow more prevalent 

 than elsewhere, and in all earthquake countries the arts 

 conducive to pleasure are highly cultivated. If, says 

 Professor Milne, the seismic force of South America were 

 turned loose in England or Germany, it would ultimately 

 produce a people with no idea of permanency, among 

 whom everything spiritual would collapse, and might 

 result in sinking Germans and Englishmen to the lowest 

 level in the ranks of civilised communities. " From one 

 section of the people we might hear a wail of misery and 

 repentance, and from another the shouts of ribaldry and 

 licentious mirth." 



Now, whilst we admit that earthquakes have a demoral- 

 ising eftect upon a population, we cannot but conclude 

 that Professor Milne has overstated his case, or that a 

 wider induction would have led him to a serious modi- 

 ficaiion of his conclusions. Living, as he does, in Japan, 

 he must know that in no independent region of Asia is 

 such progress being made in education, in art, and 

 industry as in that home of earthquakes. Surely their 

 schools, their colleges, their scientific journals, their 

 students dispatched to Europe to learn everything, 

 whether of a practical or a theoretical character, are 

 certainly not features rf " recklessness or carelessnes?," 

 nor of a " disregard for the morrow." 



