472 THE POPULAR SCIENCE MONTHLY. 



Concerning the possibility of communicating so powerful an odor to 

 a vast quantity of water by means of an almost infinitesimal amount 

 of algge, the author says : " That this odorous material was extremely 

 volatile, was obvious. It soon vanished from water left at repose in 

 the open air. Heat expelled it still more i^apidly. It was for this 

 reason that no trace of it could be perceived in the open reservoirs 

 where it could escape as rapidly as it was generated, while in the 

 closed conduit from the West Rush Reservoir to the Mount Hope 

 Reservoir, and in the street mains of the city, it was prevented from 

 escaping except Avhen a faucet was opened. Again, in its extreme 

 volatility we have the clearest explanation of the fact that so minute 

 a quantity of odorous material could infect so large a quantity of 

 water. A single flower will instantly communicate its perfume to 

 every particle of the air in a large room. A grain of musk, or a shred 

 of scorched animal tissue, will taint a vast volume of air with no loss 

 of substance appreciable to the most delicate balance." 



Regarding the public health, there is no evidence furnished that 

 warrants even a suspicion of any deleterious effect, and this is strictly 

 in accordance with what would be expected if the above explanation 

 is correct. 



To the question, " Can any measures be taken to prevent a recur- 

 rence of this trouble ?" the following answer is made : " It is useless to 

 attempt a reply until we come to understand the causes and conditions 

 precedent to such results. This knowledge can evidently be acquired 

 only by long and patient observation, if obtained at all; and, if ob- 

 tained at last, it might be only like our knowledge of the laws of 

 meteorology, which indeed enables us to predict the coming changes 

 of the weather with great certainty, but which confers on us no 

 power whatever to control it. On the other hand, it is at least con- 

 ceivable that, if we understood the life-history of these oflensive alga?, 

 and the conditions favorable or unfavorable to their growth and 

 multiplication, we might possibly be able to prevent or favor their 

 growth, or to hasten or retard their destruction in such manner as to 

 prevent the recurrence of the trouble." 



-***- 



A RUN THROUGH THE MUSEUMS OF EUROPE. 



Bt THOMAS M. BREWEE. 



N 1875-'76 the writer, having a general interest in the science of 

 ornithology, and making a special study of that somewhat neg- 

 lected branch which relates to the peculiarities of birds' nests and 

 eggs, devoted, at intervals, more than a year to visiting some of the 

 principal museums of the Continent of Europe, and afterward of 



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