316 



♦ KNOWLEDGE ♦ 



[Oct. 17, 1884. 



the falling body was so far from the ground would suffice 

 to cause such a disi)lacement as this. And since it has 

 never been found possible to secure so great a height with 

 perfect freedom from disturbing causes, the displacement 

 which has commonly had to be looked for is one measurable 

 not by inches but by lines. Even the resistance of the air 

 tends largely to diminish it. 



JSfewton suggested this method of proving the earth's 

 rotation, and Dr. Hooke, then Secretary of the Royal 

 Society, carried out the first experiment. He dropped a 

 number of balls from a height of 27 ft., and found that they 

 fell towards the south-east. This result, however, though 

 accordant with theory, cannot be depended upon, since the 

 theoretical deviation for this height is only about a fiftieth 

 part of an inch. 



Guglielmini, 113 years later, next tried the experiment 

 in the tower Degli Asinelli at Bologna. The fall was 

 about 300 ft. ; but he found that his experiments were 

 interfered with during the daytime by the vibrations 

 of the tower. He therefore worked at night, and only 

 when the air was perfectly calm. The suspended balls 

 w«re examined with a microscope until it was found 

 that all oscillation had ceased ; then they were liberated by 

 burning the thread which held them. They fell on a cake 

 of wax. So truly were the experiments conducted that 

 the greatest deviation between the holes made by the balls 

 did not exceed half a line. Guglielmini then had to deter- 

 mine where the true vertical would fall, and for this pur- 

 pose lie dropped a plumlt-line in August, 1791. Some idea 

 of the difficulty of the problem and of the delicacy of the 

 o[>erations necessary to secure success, will be suggested by 

 the fact that he had to wait half a year before his plumb- 

 liae came to perfect rest. He found, then, that the devia- 

 tion of the balls be had dropped (16 in all) was 7 4 lines 

 towards the east, and .5 27 towards the south. 



The mathematicians set to work to inquire whether this 

 result accorded with theory. They found the deviation 

 should have been but about five lines towards the east, and 

 none towards the south. On inquiry it was found that the 

 diftereuce might fairly enough be ascribed to two circum- 

 stances—first, the fact that the walls of the tower were 

 perforated in different places, and the air consequently 

 disturbed by currents ; secondly, the fact that whereas the 

 balls were dropped in the summer, the plumb-line was let 

 fall in the winter, and the tower would doubtless be 

 affected by the difference of temperature. 



But while these considerations explained the observed 

 discrepancy, they rendered the experiments valueless. If 

 scientific men were like the paradoxists they would have 

 stuck to it through thick and thin that the experiments 

 proved their position ; but, fortunately for the interests of 

 truth, scientific men are more modest, more truthful, and 

 more patient They quietly abandoned the experiments as 

 practically a failure, and forthwith instituted new trials 

 with new precautions and new contrivances to render the 

 results more trustworthy. 



The successful experiments finally conducted on New- 

 ton's method are full of interest and instruction. 



(To he C07itinued,^ 



_ _ On Saturday last, Mr. J. H. Adams, ridiug a -iG-in. " Facile " 

 ■bicycle, accomplished the astonishing distance of 266i miles within 

 •the twenty-four hours, thus beating all previous records. The route 

 was from Devizes, i-id Marlborough, Hungerford, Slough, Rickmans- 

 worth,and St. Albans, to Biggleswade, and returning by same route as 

 far as Hungerford, thence to Swindon and back, and completing the 

 time on the London road. This performance has caused considerable 

 excitement in cycling circles. On the same day Mr. E. Oxborrow, 

 3.S0 riding a " Facile," accomplished 234 miles over the same route. 



BRITISH SEASIDE RESORTS. 



FROM AN UNCONVENTIONAL POINT OF VIEW. 

 By Percy Russell. 



(Continued from p. 216.) 



GREAT as is the interest attaching to Peel and Douglas, 

 Castletown, known in Manx as Balhy Cashlal, or the 

 town of the Castle, far exceeds them both in its historic and 

 antiquarian associations. It stands on the margin of a bay 

 of the same name, and clusters about Castle Rushen, 

 originally a Danish fortress of extraordinary strength. 

 Some of the almost Cyclopean walls of this famous fast- 

 ness of the Danish tiaies are six yards thick. They are 

 constructed of very hard limestone, and such is the almost 

 imperishable character of the masonry that the marks of 

 the mason's chisels still remain in many cases distinctly 

 visible, although the work is not much less than a thou- 

 sand years old. The castle wa.s originally founded by 

 Guthred II., and has been added to during succeeding 

 epochs, so that it is in some measure a visible and most 

 instructive record of British castle architecture. Robert 

 Bruce once besieged the castle for six months, in or about 

 1313. On the shore, not far from this fortress, is a mound 

 surmounted by the remains of what was once the place of 

 execution in this ancient seat of Manx Government, and 

 here William Christian, who makes so striking a 

 figure in Walter Scott's " Peveril of the Peak," was 

 put to death by order of Lord Derby for sur- 

 rendering Castle Rushen to the Parliament. The 

 hihtory of the Isle of Man carries us far back in its 

 early authentic phases to a line of wild Welsh 

 Kings, who reigned from the sixth century for several 

 generations. A line of Norse Kings succeeded, until the 

 Manxmen, weary of their rulers, appealed for protection to 

 Edward I., and, by a formal document, submitted the 

 island to the British Crown, retaining, however, all their 

 local laws and customs. The government of the island was 

 eventually granted in perpetuity to the House of Stanley, 

 and the Earls of Derby were long Lords of Man. Even- 

 tually, by marriage, the island descended to the Athol 

 family, and in 1806 the sovereignty was bought of the 

 Duke of Athol by the British Government, and some privi- 

 leges he still retained were subsequently sold for a large 

 sum. Once on a time, the Isle of Man was undoubtedly a 

 great Druid station, and this is attested by numerous 

 archajological remains. The Isle of Man now forms a 

 separate Bishopric, believed to be as old as the year 447 

 A.D. The island, as is popularly known, has its own con- 

 stitution, laws, and courts ; and the House of Keys, self- 

 elective until 1866, is one of the most curious legislative 

 bodies in Europe. 



Few parts of the British Isles thus far north possess so 

 fine and equable a climate. This is the result, no doubt, 

 of the position occupied, sheltered at once by Irish, Scotch, 

 English, and Welsh mountains ; but the wild, rocky shores 

 are scourged by terrible tempests at times. 



Myrtles, Portugal laurel, the arbutus, and other plants 

 usually associated with a very much warmer latitude thrive 

 well, and in an orchard at Castletown a single apple-tree 

 yielded in one season 16,000 excellent apples. In the 

 winter, however, there are heavy snowstorois, and the pas- 

 toral interest suflfers severely at times. Some beautiful 

 larch-trees have been planted in places, but the sea gales 

 are very unfavourable to their growth. The oak thrives 

 well, and one lovely glen conducting from Douglas to the 

 interior should be visited by every tourist who has a soul 

 for sylvan beauty. This pl.ice is known as Glen Darrah. 



