332 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[October, 



diving bell. The General must surely have known that if Dr. Payerne 

 could generate any gas with his apparatus, it must become, at the 

 instant of its generation, of the same pressure as the air in the bell, 

 anil, to the extent of its volume, expel the water as effectually as air 

 pumped in, or otherwise introduced, under any state of compression. 

 The difficulty which is represented to have been raised by General 

 Pasley was, however, a lucky means of relieving the Doctor from an 

 awkward predicament into which he would otherwise have been placed 

 as soon as the bell was lowered into deep water. The thought sug- 

 gested itself, that General Pasley's objection might be removed by 

 attaching to the bells cylinders of highly compressed air. These cylin- 

 ders were four in number. Each one was of the capacity of four cubic 

 feet, and the air was compressed to ten atmospheres. The Doctor 

 consequentiv was provided with an available supply of air, indepen- 

 dently of the contents of the bell — and also independently of the 

 "good air" generated in the mysterious box — equal to lOO cubic feet 

 at the pressure of the atmosphere. Notwithstanding this ample pro- 

 vision. General Pasley still had misgivings of the result, the reporter 

 informs us : 



" When the preparations were completed, Dr. Payerne took his 

 seat in the diving bell accompanied by Major-General Pasley, who, 

 hating full conjdence in the goodness of the Doctor's air, but less in his 

 expedient for keeping oat the water from the bottom of the bell, took the 

 precaution of putting on a water-tight diving dress, offering another to 

 the Doctor, who rejected it, in the belief that he would be able to 

 keep the bell completely dry. They had, hoiuever, scarcely descended 

 more than 10 or 12 ftet below the surface, when the water came in upon 

 theyn so fast that the Doctor requested that the bell should be hauled up 

 out of the water, as he said he was sure that it must be leaky." 



The fact was as Dr. Payerne suspected. The air escaped from the 

 top of the bell, in consequence of the cap over the air hole not having 

 been screwed down tight. During this first attempt to descend, one 

 of the cylinders of compressed air was exhausted, though the bell had 

 been lowered only twelve feet. It does not appear whether or not 

 Dr. Payerne attempted to use his air-generating apparatus in this 

 experiment. His confidence in his resources was, however, so much 

 shaken by this first adventure, that, before going dow'n a second time, 

 he followed General Pasley's prudent example, and put on a diving 

 dress. 



In the second descent they were lowered lOi fathoms, " -when they 

 were hauled up by mistake of a signal before they had quite reached the 

 bottom.'" The three remaining cylinders of compressed air were ex- 

 hausted in this descent ; the effect of it was so far successful that it 

 kept the water within six inches of the bottom of the bell. Dr. Pay- 

 erne's assistant and Lieut. Hutchinson next descended, but as they 

 would not wait to have tlie cylinders refilled, "they were obliged to 

 make the sij;nal to stop lowering after they had only descended 23 ft. 

 the bell being at that time nearly half full of water." Thus the ex- 

 periments of the first day ended without any result. It does not 

 appear, indeed, (hat Dr. Payerne or his assistant on these occasions 

 once employed the air-generating apparatus; or if they did, it was 

 certainly of little use. 



On the second day, as on the first, there were three descents ; two 

 by General Pasley and Doctor Payerne, and one by the Doctor's assis- 

 tant and Lieutenant Hutchinson. As those were the most important 

 trials, we will give the account of them in the reporters' words : — 



"Dr. Payerne and Major-General Pasley went down twice — first to 

 the depth of 12* fathoms, when they were pulled up by mistake of a 

 signal be/ore they reached the bottom, to their great disappointment. 

 After the four cylinders were filled again with compressed air, which 

 was done in about an hour, they descended a seconil time, and as the 

 men above had strict orders not to stop lowering until the diving bell 

 reached the bottom, and not to haul it up again, unless they pulled 

 the signal line three or four times, Dr. Payerne had the satisfaction of 

 getting a small piece of wood from the wreck of the Royal George, 

 after which they made the signal to ascend. Another experiment, of 

 still greater interest, was tried at the suggestion of Lieutenant Hutch- 

 inson, who went down without any air cylinders, accompanied by Mr. 



Hardiman, having the end of one of the diver's air-pipes with them, 

 through which air was forced into the bottom of the diving-bell by 

 one of the small pumps which usually supplies air for a helmet-diver. 

 By means of this pump the water was expelled from the lower part 

 of the diving-bell, and replaced by condensed air, which enabled them 

 to descend to the very bottom, there being no cylinders to prevent the 

 bell from taking the ground, as in the former experiment; and Mr. 

 Hardiman also brought up some small relics from the wreck. 



"The result of these experiments is, that both Major-General 

 Pasley and Lieutenant Hutchinson expressed their high opinion of the 

 merit of Dr. Payerne's invention, as applied to the diving-bell; for 

 they considered that the air they breathed in the bell was perfectly 

 good; and the whole apparatus for purifying it was contained in a 

 case not larger than a common portable writing-desk, which gives no 

 trouble but that of turning a small winch or handle occasionally, and. 

 as, besides water, two very cheap and simple ingredients only are 

 used, the manipulation requires no science on the part of the person 

 in charge ; and, when the diving-bell is once filled with compressed 

 air, either by letting it escape from vessels previously filled with it, 

 as in the first experiment, or by four men pumping for less than half 

 hour, as in the second experiment, no more pumping is necessary, as 

 the air in the bell never requires to be changed." 



After carefully perusing the detailed accounts of Dr. Payerne's 

 operations under water, we entertain a very different opinion of the 

 merit of his invention from that which is stated to have been ex- 

 pressed by General Pasley and Lieutenant Hutchinson. We shall 

 now proceed to state the reasons which induce us to look sceptically 

 on the Doctor's apparatus, and to show, from well known facts, that 

 ttdiatever may be its capabilities for generating vital air, he has 

 hitherto elFected nothing with it which might not have been accom- 

 plished without any apparatus whatever, or by means that have been 

 long known. 



It has been ascertained that one gallon of air will support the life 

 of man, when the same air is inspired and expired, about one 

 minute. In a diving-bell wdiich contained 60 gallons of air, a man 

 should therefore be able to support life under water, without any ad- 

 ditional supply of air for one hour. The capacity of the diving-bell 

 at the Polytechnic Institution, which will hold six persons, is about 

 110 cubic feet ; which is equal to 870 gallons. This quantity of air 

 ought therefore to sustain the life of one man for fourteen hours. 

 The effect of breathing vitiated air for so long a time would, how- 

 ever, be most probably very injurious, consequently though a person 

 introduced in such air might continue to live for some time, it might 

 not be capable of continuing to sustain the life of one who had been 

 fur hours enduring a gradually vitiating air. But we may safely 

 assume that a man with a supply of 140 cubic feet of air might con- 

 tinue under water without much inconvenience for at least four hours. 

 Here then we have a suflScient solution of Dr. Payerne's mystery, 

 without seeking to extract the secrets of the " box." Whatever 

 latent virtue it may contain, it is clear that the Doctor might have 

 managed well enough without its development in the diving-bell of 

 the Polytechnic Institution, where he remained under wa:er in his 

 most successful experiments, three hours and a half. That he did 

 not accomplish more than could be effected by others was afterwards 

 proved most conclusively. Two persons, subsequently to the Doctor's 

 experiments, determined to try how long they could remain in the 

 bell without additional supply of air ; and without the aid of any 

 box or any apparatus whatever, they remained under water for an 

 hour and a half, during a great part of which time they burned a 

 light. The consumption of oxygen gas by two persons and a burning 

 candle for one hour and a half, must have been at least equal to Dr. 

 Payerne's single consumption for three hours and a half. It is clear, 

 therefore, that whatever advantage he might have derived from the 

 superior purity of the air (if any) manufactured by his apparatus, he 

 did not with its aid, and though he had greater inducement to suffer 

 inconvenience, remain longer under Vfater than any other person 

 might have done. 



Of the experiments at Spithead, viewed as u test of Dr. 



