1844.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



341 



nal laid down the first principles of it, it lias rendered, and daily 

 renders, eminent service. It is the calculation of probabilities, which 

 after having regulated the best arrangements of Tables of Population 

 and Mortality, teaches us how to draw from the figures, generally so 

 badly interpreted, precise and useful conclusions ; it is the calculation 

 of probabilities which alone can regulate with equity the rates of pre- 

 miums of insurance, subscriptions to tontines, poundage for superan- 

 nuations, annuities, discounts, &c. ; it is under its attacks that the 

 lottery, and so many shameful snares set by cunning for ignorance and 

 cupidity, have finally succumbed. To sum up all in one word, the 

 Analytical Theory of Probabilities is worthy of the author of the 

 Mecaritque Celeste. 



A philosopher, whose name recalls immortal discoveries, said to his 

 auditor, who were (oo much fascinated with ancient and consecrated 

 reputation, "Remember, that in matters of science, the ;iuthority of a 

 thousand is not worth the humble reasoning of one." Two centuries 

 have passed over the words of Galileo without diminishing their 

 value, and without hiding their truth. Thus, instead of displaying a 

 long list of illustrious admirers of the three splendid works of Laplace, 

 we have preferred just to glance over some of the mighty truths 

 which mathematics have there disclosed. Let us not, however, carry 

 our strictness to excess, and since chance has brought into our hands 

 a few unpublished letters of one of those men of genius to whom 

 nature has given the rare faculty of seizing, at the first glance, the 

 culminating points of objects, we may perhaps be allowed to extract 

 from three, two or three brief and characteristic fragments on the 

 Mecanique Celeste and the Treatise on Probabilities. 



On the 27th Veudemiaire, in the year X, after having received a 

 volume of the Mecanique Celeste, General Bonaparte wrote to Laplace, 

 " The first six months which I have at my disposal, shall be devoted' 

 to the perusal of your fme work." It seemed to us that the words 

 "the first six months^' take away the appearance of an ordinary com- 

 plimentary letter of thanks, and contains a just appreciation of the 

 importance and difficulty of the matter. On the 5tb, Fremaire in the 

 year XI, the reading of a few chapters of the volume which Laplace 

 had dedicated to him, was for the General " a new cause of regret 

 that the force of circumstances had placed in a career which sepa- 

 rated him from that of science. At least," added he, " I earnestly 

 desire that future generations, in reading the Mecanique Celeste, may 

 not forget the esteem and friendship which I felt towards its author." 

 On the 17th Prairial, in the year XIII, the General, then Emperor, 

 wrote from Milan, "The Mecanique Celeste seems to me destined to 

 shed a new lustre on the age in which we live." In fine, on the 12th 

 August, 1812, Napoleon who had just received the Treatise on the 

 Calculation of Probabilities, wrote from Witepsk the letter which we 

 give verbatim. "There was a time when I should have read with 

 interest your Treatise on the Calculations of Probabilities ; now, I 

 must confine myself to expressing the satisfaction which I feel every 

 time that I see you publishing new works, which improve and extend 

 the first of sciences, and contribute to the national glory. The pro- 

 gress and improvement of mathematics is intimately connected with 

 the prosperity of the state." 



I have now arrived at the conclusion of the task I had undertrken. 

 I shall be forgiven, I hope, for having shown in so much detail the 

 principal discoveries which philosophy, astronomy, and navigation, 

 owe to our mathematicians. It seemed to me that, by recalling the 

 glorious past, I showed to my contemporaries the whole extent of 

 their duties towards their country. In truth, nations in particular, 

 should remember the old adage " iiobksse oblige," nobleness obliges. 



GRAVESEND TERRACE PIER. 

 (With an Engraving, Plate XIV.) 



In the Journal for February last we gave a general description of 

 this work, which is being erected under the immediate direction of 

 Mr. John Baldry Redman, Civil Engineer, and of its then state of for- 

 wardness, and we have now the opportunity of presenting our readers 

 with drawings of the work, and a cut showing the construction of the 

 foundations of one of the main columns. 



The principal part of the work is completed, including the an- 

 preaches, the foundations, main columns, girders and platform and 

 the offices or lodges at the entrance with the clock turret and b'elfrv 

 surmounting the same. The pilaster standards to support the roof are 

 fixed, excepting those over the T head, and a large portion of the 

 upper cornice forming the guttering to thereof; also the chief por- 

 tion ot the joists of the platform, and the architrave and frieze of the 

 entablature on either side up to the T head, where some of the stair- 

 case bearers are also fitted. The foundations of the columns, con- 

 sidering the locality, have been got down in a novel manner. The cut an- 

 nexed exhibite a section of one of the foundations of the south side of 



Reference. 

 H. W., high water level spring tides 

 L. W., low water level ditto. 



the T head. The columns 

 weigh each on an average 

 9i tons, and are 28feetlong, 

 4 feet in diameter at the 

 base and 3 feet at the top of 

 the shaft, and were, as well 

 as the cylinders and the rest 

 of the heavy castings, placed 

 in position by means of tra- 

 velling machinery, as de- 

 scribed in our former notice. 

 The bases of the columns are 

 level with low water of spring 

 tides, standing upon a brick 



and stone foundation, which 



®^^^^=p^was got in in the following 

 ' manner. Cast iron cylinders 

 6 feet in diameter and J in. 

 thick, each ring being formed 

 of four segmental plates,those 

 of each ring breaking joint 

 over one another, were sunk 

 down through the bed of the 

 riverto the chalk substratum, 

 excavating the ground from 

 within them as they sunk, 

 adding additional lengths as 

 required ; they thus formed 

 caissons, or more properly 

 miniature cofferdams, the top 

 being kept always above the 

 level of high water. 



The plates varied in height, 

 being 5, 4 and 3 feet, to form 

 different heights to suit the 

 variation in the ground ; the 

 joints of those lengths left in 

 were formed with iron ce- 

 ment, as also the vertical 

 joints of the temporary 

 lengths, the horizontal ones 

 being formed with felt and 

 white lead and gaskins and 

 grease, for the convenience 

 , of taking to pieces. The 

 ^foundations of the first tier 

 i=^of columns next the abut- 

 — — ] ment were got in in the same 

 "^ ^=1 manner as the foundations of 

 the abutment, wing walls, 

 &c., viz. by excavating to 

 the required depth and sup- 

 porting the sides by timber- 

 ing, the water from the 

 r- river being kept out by a 

 f puddle bank. The cylinders 

 ' of the 2nd and 3rd tier of 

 columns were placed within 

 large ones 7 feet in diameter, 

 sunk about one-half the depth 

 required for the foundation, 

 they were kept as well as 

 the inner cylinders above 

 high water, and were sup- 

 ported by timber clamps to 

 prevent them sinking with 

 the others; the G feet cylin- 

 ders placed within were 

 thus relieved from a large 



The lowest stratum is of chalk, with an over- portion of the pressure of the 

 laying bed of flmts. the next above yellow gr^u,,,!, leaving them more 

 sand, tljen silt, above which IS mud whid,f,„, t„ sink, and sivine 



forms the bed of the river 

 a a, the cylinders'belowthis level were lefi in 



the ground and those above removed. 

 b, pipe connected with suction pipe of pump. 



C, cement bottom. 



D, brickwork in pozzolano. 



E, stone base. 



F, iron cylinders. 



G, guide frame of timber. 

 H, chain guys. 



giving 



the opportunity of guiding 

 them by wedging between 

 the cylinders. The cylinders 

 to the T head foundations 

 were sunk without these 

 outer cylinders ; guide frames 

 of timber were placed upon 

 the siiore and bolted to the 

 piles of the temporary frame- 

 29 



