236 



THE CIVIL ENGINEER AND ARCHITECrS JOURNAL. 



[June, 



by either heat or cold. This is tlic case with no other known hody, and the 

 reason of it is obvious. If water, when near its freezing point, continiu"! to 

 contract and become heavier, as other liquids do, the colder parts, sinliing 

 through the warmer, would soon reiluce the whole mass into a solid block of 

 ice, which all the following summer's heat would not be suHicient to melt; 

 the world would become ice.bound, .and its inhabitants would perish; but 

 owing to this benevolent exception to the general rule, when it has arrived at 

 a temperature below 40°, it becomes lighter owing to the expansion which 

 then begins, and the surface alone becomes frozen, protecting the water 

 below from further efiects of cold. 



With gases and vapours, expansion takes place to much greater extent 

 than with fluids. Immerse the beak of a retort in water, and apply heat ; 

 air will be expelled in large bubbles, which may be collected, and will serve 

 as a measure of the expansion that has taken place, which is also shown by 

 the quantity of water which flows in when all is cool again. The glass of 

 the retort does not expand so much as the air within does, their comparative 

 expansion being seen by reference to the following table, where is shown the 

 increase of volume of solid, liquid, and gaseous bodies, from 32° to 212°. 

 At 32' At 212° 



1000 Volumes of Air become 1375 volumes 



Alcohol „ 1110 „ 



Kther „ 1070 ,, 



Water „ 1044 „ 



Mercury „ 1020 ,, 



Glass „ 1002 „ 

 Tlie expansion of gases, though small in force, is great in bulk ; but that 

 it has force may be proved Ijy heating a small portion of air contained in a 

 bladder, when it will acquire power enough to burst the membrane with a 

 considerable report. There are a great many airs and vapours, all differing 

 from each other in their properties, but it has been found that the rate of 

 expansion is the same with them all. A volume of hydrogen gas which 

 weighs 1 ounce, the same volume of air which weighs 14oz,,or of the vapour of 

 iodine which weighs 125 oz., all expand 10 the same extent by the same quan- 

 tity of heat ; they are all expanded about J of their bulk, by an increase of 

 heat from 32° to 212°. Water, when converted into steam loses the law of 

 expansion of liquids, and acquires that of gases. When air Is expanded by 

 heat, it of course Ijecomes lighter, and rises through the atmosphere, in a 

 similar manner as water, though much more rapidly. Air enclosed in a light 

 body and heated, would consequently carry it up with it, and hence the prin- 

 ciple of the Montgolfier or fire balloon. In a crowded assembly, the air 

 becoming heated by gas and othenvise, is continually becoming li'.;hter, and 

 exerting a pressure against the roof of the building. If from any cause it 

 were suddenly heated from 32° to 212°, every 10001b. weight of air would 

 exert a force of 380° trying to lift oft' the roof; and there are some cases 

 known where, from sudden changes of temperature, it is doubtful whether 

 roofs Jiave not yielded to this pressure. It is this expansion, this rising 

 through the air of the healed panicles, which causes bad air to be dissemi- 

 nated and carried to those places where it uill be puiilicd, thus preventing 

 the accumulation of tainted air ; by this means the air wliicli we respire, and 

 which our systems have just deprived of its oxygen, rises through the atmos- 

 phere and becomes dispersed. That the breath when expelled from the mouth 

 rises in the air may be shown by suspending a bell glass fdled with muriatic 

 acid vapours over ihe head, placing a small vessel with ammonia in it in the 

 mouth, and breathing under the jar; the breath carries with it the vapours 

 of ammonia, which, rising into the glass vessel, combine w ith the acid, and a 

 white cloud of sal-ammoniac is the result. Without this provision vitiated 

 air would be breathed over and over again, and suflbcation would frequently 

 be the resul t. 



heailed screw having a collar or shoulder, and is made to pass through a hole 

 in the end of the bracket, and afterwards screwed into the underside of the 



Fig. 1 



REGISTER OF NEW PATENTS. 



(Under this head we propose giving abstracts of tlie specitications of all the moat im- 

 portant patents as they are enrolled. If any additional information be required as to any 

 patent, the same may be obtained by applying to Mr. LAXTON at the Office of this 

 JOURNAL,) 



SHIP FASTENINGS. 

 Francis Higginso.v, of Rochester, Kent, Lieut. R.'N., for " certain improve- 

 ments in fastenings for parts of ships and other vessels, which improvements are 

 also applicable to other building purposes." — Granted November 21, 1843 ; En- 

 rolled May 21, 1844. 



This invention consists in a mode of fastening the decks or planking of 

 ships to the beams or timbers, and also in joining together blocks of stone or 

 wood, which improvements arc also applicable to other building purposes. 



Fig. 1, shows a mode of fastening the [ilanking to the beams or timbers of 

 ships and other buildings ; A A is the deck or planking, and B the beam or 

 timber; C is an iron bracket which is attached to the beam by means of 

 "[multi-threaded,"^ orj other screws hereinafter^ described ; d, is a square - 



Fig. 3. 



Fig. 4. 



planking, thereby fi.xing tlie same firmly to the beam. Another mode of 

 effecting the at)ove is sliown at the opposite side of the beam, this arrange- 

 ment consists of a brass socket F, having a male or external screu- cut upon 

 it ; this socket has also a female or internal screw w hich receives the screwy ; 

 this socket is also provided with a flange / /, through which there are three 

 holes drilled which receive a key or spanner for the purpose of driving the 

 socket into a hole previously made in the planking ; the mode of fastening 

 the planking to the beams as last described, dillers from that first described 

 in the application of a screw socket only as will Ix^ clearly seen. 



Another mode of fixing planking to cast iron and other beams is seen at 

 Fig, 2, which shows a transverse section of a beam having a longitudinal dove- 

 tailed groove cut through its entire length, B is a bracket having a projection 

 C, which is made to fit the dovetailed groove, this bracket has also a hole 

 drilled through it at A. which receives a screw for the purpose of fixing it to 

 the planking as above described. 



Fig, 3 IS a Iront view of the beam, showing the mode of inserting the pro- 

 jectiim of the bracket into the longitudinal groove. There are several modi- 

 fications of this last described mode of fixing the planking to beam;, which 

 it would be unnecessary here to detail. Fig. 4 shows a mode of fixing or 

 joining together two blocks of stone or other matter, which is efl'ecled by 

 means of a screw, and screw sockets fixed into each block of stone. Another 

 Fig. 5. part of this invention consists in the peculiar formation 



of a " multi-threaded*' screw, the general form of 

 which is that of a cone, and is shown at fig. 5; these 

 screws are so made that the lower face of the spiral 

 curve or grooves are at right anges to the convex sur- 

 face of the cone, and the upper face forming an oblique 

 angle with the surface of the cone, the advantage of 

 which is not stated in the specification. 



DRESSING MINERAL ORES. 



Alexander Vivian, of Gwennap, Cornwall, gentleman, for "an improved 

 apparatus for dressing ores."— Granted Nov. 25, 1843 ; Enrolled May 25, 1844. 



This improvement consists in certain mechanical combinations, whereby 

 the operation of dressing and washing ores may, in the opinion of the pa- 

 tentee, be carried on with less expence than with machines hitherto con- 

 structed and applied to that pur|iose. The machine described in the specifi- 

 cation consists of a rectangular or oblong trough or " huddle," at one end 

 of wdiich there is an inclined plane, and at the top of this inclined plane there 

 is a cistern, having stop cocks or plugs at intervals in its side for letting out 

 the water during the operation of dressing the ores ; just below the cistern 

 there is a hopper, which extends from one side of the inclined plane to the 

 other, into which the work or ore to be dressed is placed, at the bottom of 

 he hopper there is a number of angular or "saddle back bars," placed trans- 



