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n that they shall be visible； and yet you shall look for them and not find them： after which； while you remain in the same position； I will instruct you how to see them； and you shall see them； and not merely wonder you did not see them before； but you shall find it impossible to look at the spectrum without seeing them。〃
On looking as I was directed； notwithstanding the previous warning； I did not see them； and after some time I inquired how they might be seen； when the prediction of Mr。 Herschel was completely fulfilled。
It was this attention to minute phenomena which Dr。 Wollaston applied with such powerful effect to chemistry。 In the ordinary cases of precipitation the cloudiness is visible in a single drop as well as in a gallon of a solution； and in those cases where the cloudiness is so slight； as to require a mass of fluid to render it visible； previous evaporation； quickly performed on slips of window glass； rendered the solution more concentrated。
The true value of this minute chemistry arises from its cheapness and the extreme rapidity with which it can be accomplished： it may； in hands like those of Wollaston； be used for discovery； but not for measure。 I have thought it more necessary to place this subject on what I consider its true grounds； for two reasons。 In the first place； I feel that injustice has been done to a distinguished philosopher in attributing to some of his bodily senses that excellence which I think is proved to have depended on the admirable training of his intellectual faculties。 And； in the next place； if I have established the fact； whilst it affords us better means of judging of such observations as lay claim to an accuracy 〃MORE THAN HUMAN；〃 it also opens； to the patient inquirer into truth； a path by which he may acquire powers that he would otherwise have thought were only the gift of nature to a favoured few。
APPENDIX； No。 1。
In presenting to my readers the account of the meeting of men of science at Berlin； in the autumn of 1828； I am happy to be able to state； that its influence has been most beneficial； and that the annual meeting to be held in 1831； will take place at Vienna； the Emperor of Austria having expressed a wish that every facility which his capital affords should be given to promote its objects。
It is gratifying to find that a country； which has hitherto been considered adverse to the progress of knowledge； should become convinced of its value； and it is sincerely to be hoped； that every one of the numerous members of the Society will show； by his conduct； that the paths of science are less likely than any others to interfere with those of politics。
ACCOUNT OF THE GREAT CONGRESS OF PHILOSOPHERS AT BERLIN； ON THE 18TH OF SEPTEMBER 1828。 FROM THE EDINBURGH JOURNAL OF SCIENCE； APRIL； 1829。
The existence of a large society of cultivators of the natural sciences meeting annually at some great capital； or some central town of Europe； is a circumstance almost unknown to us； and deserving of our attention； from the important advantages which may arise from it。
About eight years ago； Dr。 Okens； of Munich； suggested a plan for an annual meeting of all Germans who cultivated the sciences of medicine and botany。 The first meeting； of about forty members； took place at Leipsic； in 1822； and it was successively held at Halle； Wurtzburg； Frankfort on the Maine； Dresden； Munich； and Berlin。 All those who had printed a certain number of sheets of their inquiries on these subjects were considered members of this academy。
The great advantages which resulted to these sciences from the communication of observations from all quarters of Germany； soon induced an extension of the plan； and other departments of natural knowledge were admitted； until； at the last meeting； the cultivators even of pure mathematics were found amongst the ranks of this academy。
Several circumstances； independent of the form and constitution of the academy； contributed to give unwonted splendour to the last meeting； which took place at Berlin in the middle of September of the last year。
The capital selected for its temporary residence is scarcely surpassed by any in Europe in the number and celebrity of its savans。
The taste for knowledge possessed by the reigning family； has made knowledge itself fashionable； and the severe sufferings of the Prussians previous to the war； by which themselves and Europe were freed； have impressed on them so strongly the lesson that 〃knowledge is power；〃 that its effects are visible in every department of the government； and there is no country in Europe in which talents and genius so surely open for their possessors the road to wealth and distinction。
Another circumstance also contributed its portion to increase the numbers of the meeting of the past year。 The office of president； which is annually changed； was assigned to M。 Alexander de Humboldt。 The universality of his acquirements； which have left no branch within the wide range of science indifferent or unexplored； has connected him by friendship with almost all the most celebrated philosophers of the age； whilst the polished amenity of his manners； and that intense desire of acquiring and of spreading knowledge； which so peculiarly characterizes his mind； renders him accessible to all strangers； and insures for them the assistance of his counsel in their scientific pursuits； and the advantage of being made known to all those who are interested or occupied in similar inquiries。
Professor Lichtenstein； （Director of the Museum of Zoology；） as secretary of the academy； was indefatigable in his attentions； and most ably seconded the wishes of its distinguished president。
These two gentlemen； assisted by several of the residents at Berlin； undertook the numerous preliminary arrangements necessary for the accommodation of the meeting。
On the 18th of September； 1828； there were assembled at Berlin 377 members of the academy； whose names and residences （in Berlin） were printed in a small pamphlet； and to each name was attached a number； to indicate his seat in the great concert room； in which the morning meetings took place。 Each member was also provided with an engraved card of the hall of meeting； on which the numbers of the seats were printed in black ink； and his own peculiar seat marked in red ink； so that every person immediately found his own place； and knew where to look for any friend whom he might wish to find。
At the hour appointed for the opening of the meeting； the members being assembled； and the galleries and orchestra being filled by an assemblage of a large part of the rank and beauty of the capital； and the side…boxes being occupied by several branches of the royal family； and by the foreign ambassadors； the session of the academy was opened by the eloquent address of the president。
SPEECH made at the Opening of the Society of German Naturalists and Natural Philosophers at Berlin； the 18th of September； 1828。 … By ALEXANDER VON HUMBOLDT。
Since through your choice； which does me so much honour； I am permitted to open this meeting； the first duty which I have to discharge is one of gratitude。 The distinction which has been conferred on him who has never yet been able to attend your excellent society； is not the reward of scientific efforts； or of feeble and persevering attempts to discover new phenomena； or to draw the light of knowledge from the unexplored depths of nature。 A finer feeling； however； directed your attention to me。 You have assured me； that while； during an absence of many years； and in a distant quarter of the globe； I was labouring in the same cause with yourselves； I was not a stranger in your thoughts。 You have likewise greeted my return home； that； by the sacred tie of gratitude； you might bind me still longer and closer to our common country。
What； however； can the picture of this； our native land； present more agreeable to the mind； than the assembly which we receive to…day for the first time within our walls； from the banks of the Neckar； the birth…place of Kepler and of Schiller； to the remotest border of the Baltic plains； from hence to the mouths of the Rhine； where； under the beneficent influence of commerce； the treasurie