290 



Philosophical, Chemical, and Scienlijic Miscellanies. [March, 



Mudulus of Cuhesion. — The results which 



Mr. B. Bevan lias obtained witli regard to 



the modulus of cohesion, or tlie length in 



feet of any prismatic substance, required to 



break its cohesion or tear it asunder, are 



arranged in the following table. 



Feet. 

 Writing paper, 



foolscap 8,(HI0 



Brown wrapping 



paper, tl>in C.71W 



Bent grass (holcus) 79.IHIO 



Whalebone 14,(HW 



Bricks (FennyStrat- 



fordl 070 



Ditto (Leighton).- 144 



Ice 30(1 



Leicestershire slate 7j3U0 



Feet. 

 Tanned cow's skin lo,250 



Do. calf's do. 5,(l.)(] 



Do. horse's do. 7,illiO 



Do. cordovan 3,720 



Do. sheep's do. 5,(i00 

 Untanued horse do. ti,yijij 

 Old harness of 30 



years 5,tHKi 



Hempen twine- ■• ■7.'i,0O0 

 Catgut some years 



old 23,00(1 



Garden matting . •27,onu 



Modulus nf Elasticity. — The following are 

 the results obtained by the same gentle- 

 man as to the modulus of elasticity. 



Feet. I Feet. 



Bteel n,3i:0,0(i0 Lignum vita ■ • 1,850,000 



Bar iron 0,0f)0,(««) Teak wood 4,7(10,1100 



Ditto «,4.')0,OIIO I Yew 2,220,000 



' Whalebone 1,(H)(',ihw 



Cane 1,4(KI,IHI0 



Glxsstube 4,44ii,(i(iO 



Ice (i,(jOO,000 



Limestone, 



— Linton, Buck 2,4l.'0,000 



— Ketton l.f^OO.OOO 



— Jettemor ■ • 62."),(iOO 

 Kyegate C21,(KI0 



Yellow pine • • !),1.")(I,(«K) 



Ditto 11,1!4( 1,(1(10 



Finland deal • ■ (i,(i(i(i,(«i(l 



Mahogany 7,.''>('(l,(l()(j 



Rosewood 3,()(io,(N!0 



Oak, dry S,l(io,(HiO 



Fir bottom ■ • \ 7,4(iii,0(:0 

 2.') years old- j fi,Oli(l,(»00 

 Petersburg deal (),0{l(i,(H>.l , ^ _ 

 Lance wood . .'>,1(KI,(Kk) Yorkshire pav- 



Willow (;,2(NI,(HKI ing 1,,'!20,(100 



Oak 4,3:';!i,0(«l Coik 3,300 



."^alin wood 2,200,000 , Slate, Leicester- 

 Lincolnshire bog shire 7,800,006 



oak 1,710,000' 



Condensed Wuod. — In this age of inven- 

 tions, one of the most singidar is that of con- 

 densed wood, for which a gentleman ■* has 

 recently obtained a patent. His id«i is to 

 pass the ])lanks, which are to be cut with 

 parallel surfaces, throuirh several i)iiirs of 

 rollers, the distance between each pair pro- 

 gressively diminishing, so that the sap or 

 other moisture will be forced out of the 

 pores of the wood at the ends and sides of 

 the jilank, which will be grad'.ially com- 

 pres^ed and rendered more solid without 

 disturbing the grain, thus producing an im- 

 provement in the qiudity of wood where 

 durability and hardness are objects to be 

 obtained. 



Rockets. — The general employment of 

 the rocket as an instrument of war has led 

 to some researches as to its original inven- 

 tor. Wnether or not the Greek fire is to 

 be regarded as ot tiiis class, may admit of 

 some doubt ; but in the celebrated manu- 

 script of .Mai'cus Gnecus, there are instruc- 

 tions for the composition of gunpowder, 

 wildfire, and rockets. In a work attributed 

 to All)ert the Great, which appeared in the 

 thirteenth ccntui')', the same directions r.re 

 repeated. Roger Bacon appears to ha\e 

 been acquainted with someihing of the sort ; 

 but as neither he, nor Marcus, nor Albert, 

 have spoken of cannon, it maybe concluded 

 that the destructive engines of war, the sub- 

 ject of their allusions, were in effect rockets, 

 which correspond exactly to their descrip- 

 tions. In 1379 and 1380, the Paduans em- 



* Mr. Attley is, we believe, the name. 



jiloyed military roi'kets to set fire to the 

 town of Mestre, and the Venetians against 

 the tower IJelli' Bebe, part of the outworks 

 of Chiogia. These occurrences took place 

 almost under the eyes of the historians who 

 relate them. In 1449 Dunois used them 

 against Pont-Audemcr, which he was be- 

 sieging, and while its defenders were ex- 

 tinguishing tlie conflagration these missiles 

 had occasioned, the French troojis carried 

 tlie place. In the archives of the town of 

 Orleans it is found that previous to this, 

 viz. during the siege of Orleans in 1428, 

 various sums of money had been expended 

 in the purchase of materials proper for the 

 composition of rockets. In a manuscript 

 which in 1.5G1 was considered as old, 

 rockets are described with great minute- 

 ness. It is recommended that the cases 

 Bhould be maile of iron plate, and subse- 

 quently varnislied to preserve them from 

 rust. Louis Collado, a chief engineer of j 

 Charles V., employed them against cavalrt/,- 

 and to enlighten the outworks of besieged 

 places prior to 138G ; he recommends that 

 to increase their range, and render them 

 more destructive, the length of their tubes 

 should be increased, and petards affixed to 

 the end of them. The Barbary powers 

 even used them in naval engagements, and 

 the Asiatics have been long acquainted with 

 them. The invention consequently of Sir W. 

 Congreve has been long known, and in what 

 particular he can lay claim to originiility it 

 is difficult to say. The success which at- 

 tended the employment of this destructive 

 weapon by the British troops during the 

 last war, has led to its adoption by the 

 continental powers, and innuiiierable expe- 

 riments u])on it have been made in different 

 ))<irts of Europe. As the object is to ob- 

 tain from the materials composing the 

 rocket the greatest quantity of gas in a 

 given time and volume, it has been pro- 

 posed to substitute chlorate of potash for 

 saltpetre, and to introduce into the cxi)lo- 

 sive charge some of the fulminating jiow- 

 ders, with the i)roi)erties of which chemis- 

 try has recently made us acquainted. — 

 Revue Enci/clap. 



Yellow Fevcr.-^It has been remarked 

 that, in the city of Charlestown, in form 

 an oval, lying east and west, situated at the 

 confluence of the rivers, possessing 30,000 

 inhabitants, of whom one-third, at least, 

 arc blacks, and divided into four equal parts 

 by the spacious streets, running in the 

 direction of the cardinal points, the mor- 

 tality from the j"ellow fe\ er is in the fol- 

 lowing proportions : — One per cent, in the 

 south-east quarter ; three per cent, in the 

 north-west ; four per cent, in the south- 

 east, and five per cent, in the north-east ; 

 at the very point where the land advances 

 from tlie east into the united streams, the 

 mortality was six per cent., while on the 

 other shore of each of the rivers there 

 occurred no instance of death from the 

 yellow fever, even in an island at a small 



