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NATURE 



\Pct 17, 1878 



experiments, and after having encountered many perils, 

 and endured much suffering. With the balloon, however, 

 there is less delay, less-fatigue : " I launch," said Charles, 

 " into the air like a bird uncaged ; in ten minutes I am 

 at a height of 10,000 feet." 



If, besides, the aerostatic vray is more accessible than 

 the slope of the mountains, it is also preferable from the 

 technical point of view. It is to be remarked, in fact, 

 that -the air of high mountains is always subject to the 

 influence of surrounding glaciers. Moreover, these 

 ^powerful geological reliefs are only formed at certain 

 "joints of the earth's surface. We must not only climb, 

 but often go far in search of these abrupt and gigantic 

 ladders, while, by means of the balloon, we reach, almost 

 unconsciously, with a rapidity which is prodigious, the 

 laboratory of the principal atmospheric phenomena. M. 

 Tissandier does not deny the utility of observatories like 

 those of the Puy de D6me and the Pic du Midi, valuable 

 establishments when the services of men like M. AUuard 

 and General de Nansouty can be obtained. The problems 

 of the high regions demand for their solution more than 

 one indefatigable investigator, and, whatever be the mode 

 of investigation followed, the more numerous the workers, 

 the sooner will success crown their efforts. 



How many questions are there to solve however ! 

 Among the most interesting, and those which are now almost 

 solved, since the researches of M. Tissandier, let us note 

 the presence, in atmospheric dust, of spherules of the 

 magnetic oxide of iron whose diameter scarcely exceeds 

 the 500th part of a millimetre. These spherules, which 

 contain nickel, present a striking analogy of composition 

 with meteoric stones, and have evidently an extra-terres- 

 trial origin. They have been obser\'ed in glaciers, in 

 dust-showers like those drivea by the wind of the desert ; 

 their appearance has been noticed after the explosions of 

 bolides. The sediments' Ifeft bj^ rain-water present traces 

 of them, and M. Tissandier himself has collected them 

 on the upper steps of, the stairs of the tower of Notre- 

 Dome. \ . *■, / '"^ ., . 



To return" to' "bklloofting. Since the discovery of the 

 brothers Montgolfief, 'sljfitfe" the experiments of Charles, 

 Pilatre, and the Marqais ^'Arlandes, scarcely a century 

 has passed, and yet we can count more than 20,000 

 ascents. In this nilmbef", 'unfortunately, it would be 

 difficult to find more than 100 undertaken with an exclu- 

 sively scientific parpos^,^an.ti '^itii' the indispensable 

 instruments of observation. 



It was the physicist' Robertson who, in 1803, com- 

 menced the series of scientific explorations of the air. 

 Biot and Gay Lussac, in 1834, then Gay Lussac alone, 

 accomplished ascents which are important events in 

 meteorological investigation. In 1850 MM. Barral and 

 Bixio made an ascent characterised by very remarkable 

 circumstances. At the height of 7,000 metres they met 

 with a cloud formed, not of vesicles of water, but of 

 spangles of ice. The phenomenon has, moreover, been 

 observed in many other aerial journeys. 



M. Tissandier mentions in his book, in a very 

 special manner, the magnificent enterprises of his vener- 

 able friend, Mr. James Glaisher, who has made more 

 than thirty aerial voyages, almost always to very great 

 heights. We owe to him observations of great interest, 

 which shed a clear light on many questions, among others 



on those which refer to the decrease of temperature of 

 humidity in the various strata of air. In later times 

 MM. Camille Flammarion and De Fonvielle have devoted 

 themselves to aeronautics, not without profit to science. 

 Croce-Spinelli and Sivel, also, had made their debut as 

 masters ; their tragic fate, and the miraculous escape of 

 M. Tissandier, our readers must remember. This dis- 

 astrous journey is fully described in the volume before us. 



M. Tissandier endeavours to prove that the direction of 

 the upper atmospheric currents, their rate of translation, 

 their temperature, and their hygrometric state, can only 

 be surely established by means of the aerostat, the ob- 

 server on the earth being only able to appreciate those 

 elements with reference to superficial winds — simple 

 accidents which ought not to be confounded with the 

 true aerial rivers which often roll their enormous masses 

 above the clouds themselves. 



There is room to hope, moreover, that the balloon, 

 which has already received notable improvements, may 

 become, at no distant day perhaps, a directable instru- 

 ment, and traverse the fields of air as a ship ploughs 

 those of the sea. With these attempts at obtaining con- 

 trol over the course of the balloon, the name of M. 

 Henri Giffard is closely connected. Those who wish to 

 form some idea of what the balloon is capable as an aid 

 to the meteorologist and as a means of investigating the 

 physics of the atmosphere, could not do better than read 

 M. Tissandier' s handsome work. 



OUR BOOK SHELF 



Proceedings of the Aberdeenshire Agricultural Association, 

 1876-78. 



It has been a subject of frequent regret that while Ger- 

 many and France have been active in carrying out inves- 

 tigations upon agricultural questions few systematic 

 efforts in this direction have been made in our own 

 country. We learn, therefore, with pleasure that 

 two centres for agricultural investigations have recently 

 been started in Scotland — one by the Aberdeenshire 

 Agricultural Association, the other by the Highland 

 Society. The reports of the Aberdeenshire Association 

 for 1876 and 1877 are now before us, and demand a short 

 notice. 



The subject selected for investigation has been the 

 turnip crop, the special object of the experiments being 

 to ascertain the value of various forms of phosphatic 

 and nitrogenous manures. It is impossible not to admire 

 the pains spent on this investigation, but we are sorry to 

 say it is equally evident that the work has been done with 

 very little knowledge of the facts ascertained by earlier 

 investigators of the subject. Labour is consequently 

 spent in proving that which stands in no need of proof, 

 while discoveries are proclaimed of facts already well 

 knowTi to chemists. 



One principal point which the experiments are consi- 

 dered to have established is the little superiority of the 

 soluble phosphate of calcium over the insoluble as 

 a manure for turnips. Farmers are told to purchase 

 phosphates in whatever form may be the cheapest, with- 

 out reference to solubility. This is indeed a stai-tling 

 proposal. Mineral phosphates are at the present day 

 treated with sulphuric acid on a very large scale, with the 

 sole object of producing a superphosphate in which all the 

 phosphoric acid shall be in a soluble form : this mode of 

 treating phosphates is clearly according to the present 

 report an entire mistake. On what experiments is this 

 conclusion based? Will it be believed that in nearly 



