80 



KNOWLEDGE 



[April 1, 1895. 



Rothsch). By the courtesy of Mr. Eothschild we are 

 enabled to reproduce two beautiful photographs of these 

 birds, which, together with the information presented to 

 our readers, are taken from Mr. Rothschild's grand work 

 on the " Avifauna of Laysan." Since the limited number of 

 two himdred and fifty subscribed copies only of this work 

 were issued, both pictures and information will be new to 

 most of our readers. 



The upper parts of the white-breasted albatros are brown 



a whistling cry ; after this they begin shaking their heads 

 and snapping their bills with marvellous I'apidity, occa- 

 sionally lifting one wing, straightening themselves out and 

 blowing out their breasts ; then they put their bill under 

 the wing, or toss it in the air with a groaning scream, 

 and walk round each other, often for fifteen minutes at 

 the time." The smaller plate, which is from an instan- 

 taneous photograph, admirably illustrates, in the birds in 

 the foreground, the positions above described. 



The Wliite-Breastecl Alhatros "love-making 



and its under parts pure white. It is about thirty-two 

 inches in length and the wing measures about nineteen 

 inches. It literally covers the island of Laysan and is 

 quite fearless, so much so that when Palmer went with 

 Mr. Freeth, the director of the guano company, on 

 a tramway-line which has been constructed, a boy was 

 sent on ahead to clear the track of the young albatroses. 

 Indeed, all the birds on Laysan are so tame that, with the 

 exception of curlews and duck, they may be easily caught 

 with a large hand-net. 



The gooney lays a large white egg upon a round nest 

 made of mud, and breeds in immense colonies. Mr. 

 Eothschild thus graphically describes, from the notes of 

 his collector, the "love-making antics" of this bird. 

 " First they stand face to face, then they begin nodding 

 and bowing vigorously, then rub their bills together with 



From the "Avifauna of Laysan.' 



The full-page plate will illustrate better than words the 

 immense numbers of the white-breasted albatros on Laysan 

 Island at the time the photograph was taken, but since then 

 Mr. Freeth, who vigorously protected the birds, has resigned 

 the governorship of the island, and his successors have 

 carried off the eggs wholesale. 



THE FILTRATION OF WATER. 



By Samuel Rideal, D.Sc. Lond., F.I.C. 



THE term " filtration " is now used in a much wider 

 sense than formerly, and in such a way as was never 

 implied when the word was originally invented. 

 This has been brought about by the recent growth 

 of our bacteriological knowledge, so that we have 

 Dr. Drown, the well-known chemist to the Massachusetts 



