MS 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[May, 



runs up an ascent of one foot in three miles with a velocity of three 

 miles an hovir. 



The author enters minutely into the course of the stream, shows 

 that the point of union of the streams from the opposite channels 

 takes place on a line drawn from Carlinfjford through Peel in the 

 Isle of Man on to Morccombe Bay ; and concludes his remarks on 

 this ])art of the subject by adverting to the {rreat benefit navigation 

 will derive from the present inquiry. He then notices a chart of 

 lines of equal range of tide, which has been compiled partly from 

 tJie ranges ])uhlished by the Royal Society, and partly from obser- 

 vations made on the present occasion ; and has annexed a table by 

 the aid of which the seaman will l)e able to compare his soundings 

 taken at any time of the tide with the deptlis marked upon the Ad- 

 miralty charts. Next follows the mention of a feature in the mo- 

 tion of the tide-wave, which Capt. Beechey thinks has hitherto 

 escaped observation; viz. that the ujjper portions of the water fall 

 quicker than the lower, — or in other words, that the half-tide level 

 does not coincide with the place of the water at the half-tide in- 

 terval ; that this ditfereiice in the Bristol Channel amounts to as 

 much as four feet, and that the law seems to be applicable to all 

 the tides of the Irish Sea. 



We are next presented with a table exhibiting the various curves 

 assumed by the tide-wave, and with the durations of the ebb and 

 flood at each place. Having explained these observations in the 

 Irish Sea, the author proceeds to apply to the tides of the English 

 Channel the law which he found to regulate the stream of the 

 Irish Channel,— availing himself of the observations of Captain M. 

 White and others for this purpose. There was no difficulty in 

 adapting the rule in the upper part of the channel ; but below the 

 contractiiui of the strait, the apparent discordance was so great 

 that nothing hut a reliance on the general accuracy of the observa- 

 tions prevented the inquiry being abandoned. It seemed that the 

 streams are operated upon by two great forces, acting in opposition 

 to each other ; \iz. that there is a great ofiing stream setting along 

 the western side of the British Isles, and flowing in opposition to 

 the tides of the channel above the contraction, turning the stream 

 with greater or less effect as the site is near to, or removed from, 

 the points of influence. By pursuing this idea, it was seen that 

 the observations in the English Channel respond to it ; and then 

 applying it to the offing of the Irish Sea, and considering that 

 cliannel to comprise within its limits the Bristol Channel, as the 

 English Channel does the Gulf of St. Malo, it was found that the 

 observations there also fully bear out the idea. So that there was 

 afterwards but little difficulty in tracing the course of the water, 

 and bringing into order what before appeared to be all confusion. 

 The author then traces the great similarity of tidal ])henomena of 

 the two channels, and proceeds to describe them. For this pur- 

 pose he considers the Irish Channel as extending from a line con- 

 necting the Land's End with Cape Clear to the end of its tidal 

 stream, or virtual head of the tide at Peel ; and the English Chan- 

 nel from a line joining the Land's End and Ushant, to the end of 

 its tidal stream off Dungeness. 



With these preliminary lines, he shows that both channels re- 

 ceive their tides from the Atlantic, and that they each flow up until 

 met by counter streams; that from the outer limit of the English 

 Channel to the virtual head of its tide the distance is 2(>2 geogra- 

 phical miles — and in the Irish Channel, frtuii its entrance to the 

 virtual head of its tide, it is 265 miles. In both channels there is 

 a contraction about midway ; by Cape La Hogue in the one, and 

 by St. David's Head in the other, and at nearly the same distance 

 from the entrance. In both cases this contraction is the commence- 

 ment of the regular stream, the time of the movement of « hich is 

 regulated by the vertical movement of the water at the virtual 

 head of the channel; situated in both cases H5 miles above the 

 contraction, and that the actual time of this change, or Vulgar 

 Establishment, is the same in both cases. Below the contraction 

 of the strait, in both cases the stream varies its direction accord- 

 ing to the preponderance of force exerted over it by the offing 

 stream.. In both cases, between the contraction and the southern 

 horn of the channel there is a deep estuary (the Bristol Cliannel and 

 the Gulf of St. Malo) in which the times of high water are nearly the 

 same, and where, in both, the streams, meeting in the channel, 

 pour their waters into these gulfs, and in both raise the tide to the 

 extraordinary elevation of forty-seven feet. From the Land's End 

 to the meeting of these streams in one case is seventy-five miles, 

 and in the other the same. 



In one channel, at Courtown, a little way above the contraction, 

 and at 150 miles from the entrance, there is little or no rise of the 

 water ; and in the other, about Swanage, at the same distance from 

 the entrance, there is hut a small rise of tide also (five feet at 

 springs). In both eases these spots are the node or hinge of the 



tide- wave, on either side of which the times of high wafer are re- 

 versed. And again, near the virtual head of the tide, in both 

 cases, there is an increased elevation of the water on the smith-east 

 side of the channel of about one-third of the column — the rise at 

 Liverpool being thirty-one feet, and at Cayeux thirty-four feet. 



The author traces a further identity in the progress of the tide- 

 wave along the sides of both chsinneh 0])pnsite to that of tlie node. 

 In the first part of the channel the wave in each travels at about 

 fifty miles per hour ; in the next, just above the node, this rate is 

 brought down to about thirty miles in one, and to sixteen miles in 

 the other ; it then in both becomes accelerated, and attains to 

 about seventy-six miles per hour. Lastly, the author observes 

 that the node or hinge of the tide, placed by Prof. Whewell (in his 

 papers on the tides) in the North Sea, is situated at the same dis- 

 tance nearly from the head of the tide off Dungeness, as the node 

 near Swanage is on the opposite side of it ; and that in the Irish 

 Channel, at the same distance nearly as the node at Courtown is 

 from the head of the tide off Peel, there is a similar spot of no rise 

 recently observed by Capt. Robinson. Capt. Beechey's letter was 

 illustrated by charts and diagrams, showing the identity and singu- 

 lar phenomena of these two great channels. 



MR. HAY'S THEORY ON SYMJIETRICAL BEAUTY. 



On the Production of the Beautiful — an attempt to prove that the 

 Theory advocated in ttte Papers read by Mr. D. K. Hay before the Society ^ 

 founded on the development of the Harynonic Ratios, is fallacious. By Mr, 

 Thomas Purdie. — (Head at the Koyal Scottish SocietT of Arts, March 

 13 aud 27). 



Part I. 



Mr. Purdie commenced his paper by referring to the opinions of those 

 philosophers of the Socratic school whose names had been used in support 

 of the tlieory under consideration. He endeavoured to show, hy quotations 

 from Lord Jefifrey's " Essay on Beauty," and from Dr. Reid's works, that these 

 opinions were hostile to all theories of such a nature. He next adverted to 

 Vitruvius, and stated that he propounded a theory of a similar character to 

 that whose fallacy he had undertaken to prove. One of the diagrams used 

 by Vitruvius in applying his principles to practice was exhibited ; the same 

 diagram bein^ used by the author of this theory in explaining the harmonies 

 of the Parthenon. He stated, however, that Vitruvius could not be con- 

 sidered as an authority in regard to the principles on which styles are founded, 

 having been led away by his fondness for metaphysical distinction and re- 

 finement, to refer them to sources with which they had no connection. This 

 statement was supported hy quotations from the works of Vitruvius himself, 

 from Lord Aberdeen's " Principles of the Beauty of Grecian Architecture," 

 and from the article .Architecture in the " Encyclopaedia Britannica." 



As the second division of his subject, Mr. Purdie referred to the labours of 

 Kepler in proving the harmonies and analogies he supposed to exist through- 

 out nature — to prove which, great part of his " Mysterium Cosraographicum" 

 and " Harmonices Mundi" were written. He investigated the reason of the 

 Zodiac being divided into 360 degrees. It led him into some subtle con- 

 siderations in relation to the divisions of the musical scale. Mr. Hay inves- 

 tigates the properties of the number 360, and his investigation seems to lead 

 to a conclusion of a similar nature. — (See p. 24 of his book on Symmetrical 

 Beauty). A quotation was read from one of Galileo's Dialogues, denouncing 

 the belief prevalent in his time as to the beauty supposed to reside in the 

 harmonic ratios, that being the principle on which the present theory is 

 founded. lie quoted a passage from Bacon, tending to show that be con- 

 sidered the ideal beauty of the Greeks, and that formed by geometrical pro- 

 portion, to be antagonistic. In it Bacon contrasts Albert Durer, " who 

 would make a figure by geometrical proportions," with Apelles, " who would 

 choose the best parts out of diverse faces to make one excellent." — Numerous 

 quotations were given from various authors, as to the universal prevalence,,ia 

 the 15th century, of the " dangerous ideas of the aptitude and congruence of 

 numbers,'' and of the absurdities to which the style of reasoning from 

 analogy lead. By this, Francesco Sizzi attempted to disprove the existence 

 of Jupiter's sateihtes. A celebrated musician held that God created the 

 world in six days, and rested the seventh, because there are but seven notes 

 in music ; and Kepler, by a similar process, explained the music of the 

 spheres, in which Saturn and Jupiter were proved to take the bass. Mars the 

 tenor, the Eaith and Venus the counter-tenor, and Mercury the treble. 



As the third division of the subject, Mr. Purdie gave a short account of 

 the theory advanced by Alison, advocated by Lord Jeffrey and others, and 

 generally recognised by modern metaphysicians. He did not feel himself 

 qualified to enter on the differences existing between Alison, Lord Jeffrey, 

 Payne Knight, and Dugald Stewart. They appeared to be as much of a 

 philological as a metaphysical nature, and did not affect bis branch of the 

 subject. He had not had time to make himself acquainted with Sir George 

 M'Kenzie's refutation of Alison, and could uot say what effect it might have 



