1839.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



411 



had eiiilowerl liim. Darwin one day said to the members, " I have been 

 thinking of a kind of pen witli two nil)s, by which any tiling may be written 

 twice, so as to give at once tlie original and cojiy of a letter." *' I hope," 

 replied Watt almost directly, " that I shall find out a better way of doing it ; 

 I will think of it to-night, and let you know to-morrow." The next day the 

 copybui-maeliine was invented, and even a slight model sufficiently advanced 

 to show its effects. This machine, which is of such utihty, and so generally 

 used in English offices, has lately received several improvements, which have 

 been claimed by different persons ; but I can affirm with certainty, that the 

 present form was actually described and drawn in 1780 in the patent of our 

 colleague. 



The apparatus for heating by steam is of three years' later date ; Watt 

 made use of it in his own house in 1783. It must be observed that this in- 

 genious process was already pointed out by Colonel Cooke in the PhUosophi- 

 cal Transactions for the year 1745 ;* but the suggestion was quite unattended 

 to. Watt, at all events, has not the merit of reviving it ; it was he who first 

 applied it, and it was from his calculations of the extent of surfaces necessary 

 for heating rooms of different sizes, which at first served to regulate the 

 application of this process. 



If Watt, in the course of his long career, had only produced the engine with 

 a separate condenser, working steam expansively, and the jiarallel motion, he 

 would hold a first-rate rank among the small nundjer of those whose lives 



Fig. 16. 



BtleKous. 



DOUBLE ACTING ENGINE, FOR SUPPLYING WATER. 



Fig. 16, represents an engine, with the several parts before explained, com- 

 bined in one view. 



The steam, from the boiler, passes by the pipe S, thronsh the valve a, and 

 forces down the piston p to the bottom of the cylinder C ; juu before the piston 

 arrives at the bottom, the pin on the rod of the air pump corn's in contact with 

 the lever and reverses the valves, by shutting the valves a.b, and opening c, d, 

 which were shut ; the steam will now pass down the vertical pipe S, through 

 the valve (/, and force up the piston p to the top of the cylinder, at 'the same 

 time the steam, wliich forced it down, will escape through the valve b, to the 

 condenser B, by a pipe, which conveys the steam from the valves to the con- 

 denser. Thus one double stroke of the engine is performed, and the valves 

 again restored to their original position;—! is the handle to the injection cock 

 for supplying a jet of water into the condenser B, which liquifies the steam • the 

 condensed water, together with the air, is removed by the aid of the air pum'p A, 

 worked by the rod R, attached to the beam of the engme, and discharged 

 through the valve at the top, into the hot well, where part is forced back to the 

 boiler, by the force pump L, and the remainder is allowed to run to waste • N is 

 the cold water pump, also worked by a rod attached to the beam, for sunnlying 

 the condensing well ;--Y is the governor, before explained, which is connected 

 with the crank R by the horizontal rod, and regulates the throttle valve in the 

 honzontal steam pipe S;— O is a connecting rod, attached to the end of the beam 

 and, at the lower part, to the crank that turns the fly wheel P, which equalizes 

 the power of the engme ;— M is a rod for the purpose of working the pumn d' 

 to raise water— when the piston descends, the water contained in the pump' 

 Vill be forced through the lower valve, up the pipe G, into the upper air vessel 

 J2, thence it passes, in a continued stream, t« an elevated reservoir- as the piston 

 of the pump is descending, a fresh supply passes up the pine F, through the 

 upper valve, into the superior portion of the pump, and which, when the piston 

 rises again, is forced through the opposite valve, into the air vessel E as before 

 and also, as the piston is being raised, a fresh supply of water passes throu-h 

 the lower valve, Irom the pipe F, and refills the pump, as at first. 



* I have read in a wi>rk by Mr. Robert Smart, Ihat Sir Hugh Plalle had foreseen 

 before Colone Cook, l he applica.i.m of sieam fur heating apartments. In the a.uhor" 

 Garden o. Eden pnblished in ItiCO, he suggests somelhing analagous for tl rpre 'erv ,- 

 lion of plants m bol-hnases. Sir Hug), Platte proposed to place coverin,, o( t"^ ,! " f 

 othe metaUverthevesselsm whuh meat is eoukert, and then to send throndi < pen inu 



make an epoch in the annals of the world. Well ! his name seems to me to 

 be attached with credit also to the greatest and most prohfic discovery of 

 modern chemistry — the discovery of the composition of water. My asser- 

 tion may appear rash, for numerous works, in which this important part of 

 scientific history is treated authoritatively, make no mention of the name of 

 Watt. I trust, however, that you will follow up tliis discussion without pre- 

 judice, that you will not allow yourselves to be diverted fi'om the investi- 

 gation by authorities, which are less weighty than is generally supposed ; 

 and above all, that you will not forget to remember how few authors, in these 

 days, trace up a subject to its original source ; how troublesome it seems to 

 them to expose themselves to the dust of a library-, and, on the contrary, how 

 convenient it ajipears to be to reduce the whole labour of a work to the mere 

 effort of compilation. The task which your confidence has entrusted to me, 

 seemed to impose more serious obligations. I have hunted up numerous 

 printed documents, and all the papers of a voluminous correspondence still 

 in manuscript, and if fifty years after the event, I appear to claim, in favour 

 of James Watt, an honour too carelessly gi-anted to one of his most illustrious 

 countrymen, it is because it seems to me useful to show that in the bosomi 

 of academies truth makes way sooner or later, and that, with regard to in- 

 ventions, there is no prescription which can be claimed, or act of limitation 

 imposed.* 



The four fictitious elements, fire, air, water and earth, the various combina- 

 tions of which are to give birth to all known bodies, are one of the numerous 

 legacies of that brilliant philosophy wdiich for ages dazzled the noblest in- 

 tellects in the world, anil led them astray. Van Helmont, first shook, al- 

 though slightly, the principles of this ancient theoi-y, by calling the attention 

 of chemists to several permanently elastic fluids, several airs in fact, which 

 he termed yases, and the properties of which differed from those of common 

 air, the supposed element. The experiments of Boyle and Hooke raised diffi- 

 culties still more serious, they proved that coinmon air, wliich is indispensable 

 for respiration and combustion, exliibited in these two phenomena notable 

 changes in their properties, necessarily implying the idea of composition. 

 The numerous obsei-vations of Hales ; the successive discoveries of carbonic 

 acid by Black ; of hydrogen by Cavendish ; of nitrous acid, oxygen, muriatic 

 acid, sulphurous acid and ammonia by Priestley, definitively disposed of the 

 ancient idea of a simple and elementary air among those chance conceptions, 

 almost always false, which are the offspring of those who have the audacity 

 to believe themselves called not to discover, but to guess the mysteries of 

 nature. 



In the midst of so many remarkable circumstances, water still preservec! 

 its elementary character. The year 1776 was at last signahsed by an obser- 

 vation which was to bring about the subversion of tliis general belief. It 

 must be acknowledged that from the same year, also are to be dated those 

 singular efforts which were a long time made by chemists to disbelieve in the 

 •natural consequences of their own experiments. The observation to which 

 I am going to refer was made by Macquer. 



This judicious chemist baring placed a white porcelain saucer over the 

 flame of some hydrogen gas which was burning quietly from the neck of a 

 bottle, observed that this flame was without any smoke properly so called, 

 and that it deposited no soot. That part of the saucer which was touched 

 by the flame was covered -Hith driplets evident enough of a fluid similar to 

 water, and which on examination proved to be pure water. That was most 

 certainly a singtdar result. You must notice that it was in the middle of the 

 flame, in the part of the saucer touched, that the driplets of water were de- 

 posited. This chemist however did not pay attention to this fact, he was not 

 surprised at what was really surprising ; he merely mentions it without any 

 remarks, he did not perceive that he had a great discovery at his finger's ends. 



Does then genius in sciences of observation consist of the faculty of saying 

 at the right moment, whi/ ?f 



The physical world reckons volcanoes which have never made but one 

 eruption, and in the intellectual world similariy there are men, who after one 



• M. Arago now comes to another of fhe wonderful discoveries which are to confer 

 honor on liis memoir, and exhibit the novelty of his views, and he does well to blow tlie 

 trumpet before the Shiloh which he promises. The 'parturient monies' is a result but 

 too customary with M. Arago lo call tor reni:irfc ; it is sullicient to repeat the trite saying, 

 that he has nothing which is new thai is tine, and iiltfe Ihal is true which is new. He 

 certainly has the merit of stepping first in a career, which none of Walt's admirers hart 

 ever yet the hardihood to imai^iiie that it wonlil be wt.rth Ihe while of him or his idol 

 to pursue, and he may claim all the merit of research in a subject which admits of little, 

 and in which Ihe great deal be assumes has been thrown away upon error. — IVote of 

 the Tratmlator. 



t M. Ara^o, led away by the quibbling iynusfatnus of his own imaginatioD, stops to 

 give a new definiliou of genius, soinelhing bke that which defines man to be a cooking 

 aninial, or an unfledged fowl. M. Arago, politician and philosopher, academician and 

 deputy, Li considered, by some, to be the Lord Brougham of France, and, led away by 

 the vanity of figuring as an orator in tlie chamber, and as a rhetorician in the academy, 

 he deserts those studies in w-hich alone he succeeded, and from which alone he can de- 

 rive a solid reputation. If he resemble Lord Brougham, lie resembles that great man 

 in bis defects, rather than iu his talents, and has the same point of contact as the lower 

 members of the animal kingdom have witli their exalted fellow man. M. Arago ileserts 

 tlie care of science to exhibit as an orator; Lord Brougham, like Cicero, possessing an 

 eloquence, which tlie fears evcl> of his enemies do not allow them to dispute, dedicates 

 his leisure to severer studies. M. Arago may have the superficiality of Lord Brougham, 

 but he wants his elegance of style, and clearness of reasoning, the variety of his studies, 

 and the skill with wduch it is brought to bear on Ihe subject of his research. If Brougham 

 be exposed to this charge, he amply makes up in breadth what he loses in depth, while 

 M. Arago without elotpience in matters of science, mistakes declamation for an easy 

 rio.v of language, and Ihinks to supply the logic of the advocate with the c&ncPiti of llic 

 middle ages. M. Arago might be the ' niagisler morum' in Ihe schools of science, bua 

 in the world at large he is only a D-drrow-uiiuded and conceited pedagogue. — Ao.'e of tlm 

 Translator, 



