1840.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



247 



AA'e also feci ourselves opposed to the majority of the comiietitors as re- 

 gards a feeling wliich they eviiiee against engine-men as a body. In any 

 large class of society, there arc always to be found individuals, whose im- 

 proper conduct no laws can restrain ; and we are inclined to think that the 

 nundicr of engine-men who recklessly endanger their own lives and the pro- 

 jierty under their charge, are nearly in the same projiortion to the mass of 

 . engine-men, as felons arc to the mass of society, notwithstanding of the 

 watchful superintendence of the immense army of the law. 



In a matter of such importance to the public, and to the proprietors of 

 steam engines, wc cannot avoid expressing our regret, that in the cases of 

 explosion which have occurred, there are no scientific rejjorts of the appear- 

 ance and state of the engines, valves, or boilers. If a reguhatiou were 

 adopted by the local .lutliorities, requiring intimation of every case of acci- 

 dcuit, and obtaining thereafter, before any alteration had been made on the 

 damaged boiler, machinery, or buildings, a detailed report of their situation 

 and ap]>carance, we are of opinion that more certainty \vould soon be given 

 to the conjectiu'al causes which jirodnce such accidents; and that, in coiise- 

 ipicncc, in the construction or management of steam engines, means would 

 be adopted which woidd lessen the chance of their reciuTence. 



In regar<l to the appointment of inspectors, whieli some of the competitors 

 recommend, we beg to express our doubts as to the expediency of this mea- 

 sure. They must either lie armed with discretionary powers, to admit or 

 reject any alteration in construction or managenicnt of the machinery — in 

 which case the immense amount of capital invested in steam vessels at each 

 port must be subjected to the individual caprice of the inspector — or it will 

 be necessary, in order to furnish them with ]irecise instructions, that tlic.\ct 

 of Parliament by which they are apjiointed, shall regulate what are and what 

 are not infallible securities against accidents of every kind. 



^A'hen we comjiare the almost innumei'able multitude of jiersons who have 

 amiually availe<l themselves of steam conveyance at sea and on railwavs, for 

 many years past, witli the niunbcr of accidents that have occurred, it is 

 gratifiing to us to consider, that, with our attention so closely turned to the 

 subject as it has been for some time, we not only cannot trace any cause of 

 alarm, Init are able to express our conviction, that it is the safest means of 

 transport that now exists. 



In conclusion, we beg to report our opinion, that a combination of the 

 plans we have recommended to yoiu' notice miglit he advantageous, provided 

 the attachments l>y which they are connected with the safety-valve be sueli, 

 as that by no derangement of the new apparatus, can the former be prevented 

 from acting. But we can view them only in the light of experiments, which 

 will rerpiirc some time of watchful superintendence, to ascertain their mode 

 of operating under various circumstances, and to detect and remedy errors in 

 their construction. 



ExTHACT FROM AoniTIONXL KkpORT. 



In compliance with this instniction, we have no hesitatiou iu recommend- 

 ing to you the jilans marked by the Committee Nos. 2 and 41, lodged by 

 Mr. .Tames D. Xeilson and Mr. George Mills, both of Glasgow. It will be 

 evident on inspection, that they are identical in design, and that the dift'c- 

 rence in their proposed construction is quite immaterial. (See Figs. 1 and 2.) 



For the reasons stated in our General Report, we conceive thent to be the 

 best of the designs submitted to the Trustees for jireventing explosion. 



You are farther pleased to request, that we should name " the three jier- 

 sons who have brought forward, in your opinion, the three next best plans, 

 so as to enable the Trustees to consider whether any portion of the aildi- 

 tional Sinn of One Hundred Pounds, allocated by the trustees, is, in the cir- 

 cumstances, fairly and justly due to any of the competitors who may be 

 unsuccessful in obtaining the princijial premium of One Hundred Pounds." 



From the extreme similarity in design and execution of the plans which 

 appear to us entitle to rank in the second class, we are unable to reduce 

 their number to less than four, viz., those numbered by the Committee 4, 

 3S, .').), and hi'i. which were severally lodged — the three first by Messrs. 

 Allan Clarke ami David Thomjison of Glasgow, and Mr. John Baird of Shotts; 

 and the last, the joint production of -Messrs. AVilliam Ncilson and William 

 Muir of Glasgow. 



Mr. Oavid Thom|)son st.itcs that bis design has been in use at Messrs. 

 Roulton & AVatt's Engine Factory at Soho; and, as stated in the General 

 Keport, the otljcrs are precisely similar to apparatus in common use in vessels 

 on the Thames, the Clyde, and the Mersey; and, through the politeness of 

 the commander, there was exhibited to one of the reporters, on lioard of the 

 French Government steam vessel, " Le Jleteorc," arrangements for working 

 the safety-valves, which were similar in design and mode of o|ieration to the 

 jilans in Nos. 38, a."), and 56. 



As we are of ojiinion that the premiums ofl'ered by the Clyde Trustees 

 were for apparatus presenting .some novelty of construetion. and possessing 

 means of security beyond that which the existing safely-valvea and con- 

 nexions have been supposed to afford, wc do not, under this impression, con- 

 sider these gentlemen entitled to participation in the second premium ; but 

 leave this to the decision of the Trustees. 



AVe have no other remarks to offer to your consideration on the residue of 

 the plans. 



FROCSEDINGS OP SCIEKTIFIO SOCIETIES. 



ROYAL SOCIETY. 



March 12. — The Marquis ok Northampton, President, in the Chair. 



The following papers were read : — 



" On certain rtiria/ionx of the mean heiijltt of the Barometer, mean Tem- 

 perature, and depth of Rain, connected v:ith the Lunar Phases, in the cycle 

 of years from 1SI5 to 1823." By Luke Howard, Esq. 



The table given in this pajier contains the residts of calculations relating 

 to the objects specified in the title, cast into periods of six, seven, or eight 

 days, so as to bring the day of the lunar phase belonging to it in thc'niiddle 

 of the time. The observations were all nuide in the neighbourijiod of Lou- 

 don. It appears from them that in the period of the last quarter of the 

 moon the barometer is highest, the temperature a little above the mean, and 

 the depth of rain the smallest. In the |ieriod of the new moon, both the 

 barometer and temperature are considerably depressed, and the rain increased 

 in quantity. The intluence of the first quarter shows itself by the further 

 depression of the barometer ; hut the temperature rises almost to the point 

 from which it bad fallen, and the rain still increases, but not in au equal 

 ratio. Lastly, the full moon again reduces the temperature, while the baro- 

 meter attains its maximum mean height, and the quantity of rain is the 

 greatest. Thus it appears, that during this lunar cycle, the approach of the 

 last quarter is the signal for the clearing up of the air, and the return of 

 sunshine. 



'* On the theory of tite Dark Bonds formed in the Solar Spectrum, front 

 partial interception by transparent plates." By the Rev. Baden Powell. 



This paper contains the mathematical investigation of the phenomena of 

 peculiar dark bauds crossing the prismatic spectrum, when half the pupil of 

 the eye, looking through the prism, is covered by a thin plate of any trans- 

 parent substance, the edge being turned from the violet towards the red end 

 of the spectrum ; and which were first noticed by Jlr. Fox Talbot, and were 

 ascribed by Sir David Brewster to a new property of light, consisting of a 

 peculiar kind of polarity. The author shows, that on the undulatoiy theory, 

 in all cases, a dirt'erence of retardation between the two halves of each pri- 

 maiy pencil throughout the spectrum, may give bauds within certain limits; 

 and that it affords a complete explanation of the phenomena in question. 



March 19. — The Makquis of Northampton, President, in the Chair. 



The following paper was read : — 



" Contributions to Terrestrial Marjiieiisnt." By Major E. Sabine. 



An increased activity has recently been given to researches in terrestrial 

 magnetism, with the definite object of obtaining correct maps of the mag- 

 netic phenomena, eorresponding to the present epoch, over the w hole surface 

 of the globe. To aid these researches, and to facilitate the comparison of 

 the general theory of M. Gauss with the facts of observation, maps have been 

 constructed of the magnctical lines, both as computed by the theory, and as 

 derived from observations already obtained. The theoretical and actual hues 

 of the declination and intensity h.ave thus been represented in majis reeeutly 

 published in Germ.any and England, as have also the lines of the inclination 

 computed by theoiy ; but the corresjionding map or the latter element de- 

 rived from observations is yet wanting. Tlie object of the present communi- 

 cation is to supply this desideratum, as far as regards the portion of the 

 globe contained lietween the parallels of 5.')- X. amt.").!" S., and the meridians 

 of 20' E. and 80° ^\■. ; comprising the Atlantic ocean and the adjacent coasts 

 of the continents on either side. The observations chiefly employed for this 

 liurpose are two series made at sea ; one by Mr. Dunloji, of the Paramatta 

 oiiservatory, iu a voyage from England to New South Wales, in 1831 ; the 

 other by Lieut. Sulivan, of the Royal Xnvy, in a voyage from England to the 

 Falkland Islands and back, in 1838 and 183!). Thii observation of the mag- 

 netic dip at sea, which was commonly practised by the distinguislied navi- 

 gators of the last century, was unfortunately not resumed when the interest 

 in such researches was revived on the restoration of peace; but it is by such 

 observations only that the lines of ineUnation can he independently traced 

 over those large portions of the globe which are covered by the ocean. The 

 difficulties which attend the observation, occasioned by the motion and the 

 iron of the ship, require the adoption of several jireeauVious, which it is par- 

 ticularly desiralile at this time to make generally known. The series of 

 Messrs. Dnnlop and Sulivan are discussed in this view ; and the value of 

 results obtained under circumstarices of due precaution is pointed out by 

 theii- success. The position of the lines on the land poition of the map is 

 derived from 120 determinations in various parts of Europe, Africa, and 

 Amei'ica, between the years 1834 and 1839, of which about the half are now- 

 first communicated. The series of Messrs. Dnnlop and Sulivan contain also 

 observations of the magnetic intensity made at sea ; Mr. Dunlop's by the 

 method of horizontal vibr.ations, and Lieut. Sulivan's !jy the instrument and 

 method devised by .Mr. Fox. Tlie degree of precision which may be obtained 

 by experiments thus conducted, is shown by the comparison of these obser- 

 vations with each otiier, and with the isodynamic lines previously derived 

 from observations made on laud. The first section of this paper concludes 

 with discussions on the relative positions of the lines of least intensity and of 

 no (Up, and of the secular change which the latter line has undergone in the 

 ten years jireceding 1837. In the second section, the observations of Mr. 

 Dunlop are combined with recent observations on the coasts of Australia, by 



