760 



THE POPULAR SCIENCE MONTHLY. 



ana, he found from three to sixteen per 

 cent, of the hogs afiected with trichinae, the 

 number of hogs diseased varying greatly in 

 differeut localities. 4. That ninety per cent, 

 of the disease produced by trichinous pork 

 appears as gastero-enteritis, diarrhcea, or 

 dysentery, ten per cent, only representing 

 the cases of trichinosis proper. 



Penetrating Power of Different Colored 



Lights. An experiment was lately made at 

 Trieste, to determine how far lights of 

 different colors penetrate darkness. Half 

 a dozen lanterns with carefully -selected 

 glass, and all furnished with oil and wicks 

 of the same quality, were lighted on the 

 beach, and then observations were made by 

 a party in a boat. At the distance of half 

 a league, the dark-blue lantern was invisible, 

 and the deep-blue one nearly so ; hence it 

 appears that blue lights are not adapted for 

 use in lighthouses, or as signals. Of all the 

 colors the green was visible for the longest 

 distance, with the exception of the red, 

 which ranked next to the white in power of 

 penetration. Tlie conclusion is, that only 

 the green and the red arc suitable for sig- 

 nals ; and the green light the Trieste ob- 

 servers only recommend for use in conjunc- 

 tion with white and red lights, inasmuch 

 as, when viewed from a short distance, an 

 isolated green light begins to look like a 

 white one. 



Carious Freak of the Cnrly-Willawr 



The following curious facts are communi- 

 cated by Dr. S. Lockwood to the Botanical 

 Bulletin: " We have two pendent willows, 

 known as S-ilit Bjlylonica (more correctly 

 S. pendula, Moench.), the weeping-willow, 

 and Salix crinpj, the curly-willow. On the 

 grounds of Hon. E. W. Scudder, Trenton, 

 New Jersey, is a fine specimen of each, the 

 two having a clear distance of twenty -five feet 

 between tiieir nearest branches. The top- 

 most branch of the curly-willow, on the side 

 of the tree next the weeper, is about ten 

 feet long, and six feet thick, and is densely 

 covered with leaves. The curious fact is, 

 that while the rest of this entire tree has 

 the perfect habit of S. crispa, this large 

 branch has the perfect habit of S. Bahyloni- 

 ca. The long pendent branchlets, and every 

 leaf, are in all respects those of the weeping- 



willow. This is true not only of the form 

 and habit of the leaves, but with positive 

 exactness also of the color. The true crispa 

 leaves are a very dark and shiny green 

 above, and almost a chalky white under- 

 neath. The pseudo-Bahi/lonica leaves are a 

 pale yellowish-green above, and still paler, 

 perhaps pea-green, on their under sides. I 

 compared them carefully with the leaves of 

 the neighboring Babj/hnlca, and, excepting 

 perhaps that the leaves cf the freak were a 

 little the smaller, a fact of no significance, 

 there was no difference whatever. Looking 

 at this great branch, the spectator comes to 

 regard it as a natural graft. This is an ut- 

 ter mistake. It is purely an outcropping of 

 heredity, and is thus an interesting evidence 

 of the identity of species in the curly and 

 the weeping willow. Supposing S. Bahyhnica 

 to be the ancestor, we have here the long- 

 dormant inherited force asserting itself, and 

 proclaiming the ancient and wellnigh lost 

 parentage of S. crispa. It is observable, too, 

 that the foliage of the branch, thus repre- 

 senting the true weeper, is much more dense 

 than that on the rest of the tree represent- 

 ing the curly-willow. This is the fact re- 

 specting these trees everywhere. The curly- 

 willow has this to its disadvantage, its pau- 

 city of foliage, so that, in pointing back to 

 its ancestry, it declares tlie leaf-wealth of 

 the ancient line. As the tree is a very old 

 one, it is significant that this declaration of 

 heredity shoul'd appear so late in life." 



A Wise Public Bcnefaetor. In 1868 Sir 



Joseph Whitworth presented to the British 

 nation an annuity of 3,000 per year, which 

 was vested in the Department of Science 

 and Art, for the purpose of founding schol- 

 arships to promote the instruction of young 

 men in the theory and practice of mechan- 

 ics and the cognate sciences. He has now 

 made over to the public his large landed 

 estates for similar purposes, reserving to 

 himself a life interest. The Department 

 of Science and Art is to hold the estates, 

 subject to the control of Parliament. In 

 commenting upon this munificent action of 

 Sir Joseph Whitworth, the London Times 

 commends his wisdom in trusting Parlia- 

 ment to adapt his endowment to the va- 

 rying circumstances of successive times. 

 " We have had," says the Times, "abundant 



