368 



SCIENCE. 



placed them in a cauf, and have never had one die from 

 the change. The change to fresh water undoubtedly 

 hastens the metamorphosis into the Amblystoma form, as 

 I have noticed quite a change in the course of twenty-four 

 hours in individuals placed in the cauf, while an equal num- 

 ber kept in the alkali water in the boat have shown no 

 change in any of them in several days. I have kept six 

 at different times in jars of fresh water until they have 

 completed their metamorphosis. I made no systematic 

 note of appearance from day to day, but my observation 

 was careful and regular. In two cases the change in ex- 

 ternal appearance was so abrupt that I would have been 

 almost certain that another salamander had been substi- 

 tuted for the one in the jar had I not had him so com- 

 pletely under observation that it was impossible. The gills 

 had assumed a stubby form about half the length that 

 they were the night before, and the gill on the back on the 

 back of the body was nearly half gone ; it took air quite 

 often, and I removed it from the jar and placed it in a box 

 with some lake grass around it to keep it moist. It com- 

 pleted the metatmorphosis in a few days. I did not feed 

 it any during this time. While it was in the jar it was 

 well fed with flies. The jar was placed upon a table in 

 the telegraph office. The flies at first had to be pushed in 

 front of it with a pencil. It finally got to know that tap- 

 ping the jar with a pencil meant a fly, and would rise to 

 the surface immediately and snap at whichever it saw first, 

 pencil or fly. It furnished train-men continual amusement 

 while here, and they kept it constantly gorged. Those 

 that I kept well fed in jars and seldom changed the 

 water, say once in three days, usually began to 

 show a slight change in from two to three weeks, 

 and all of them completed the change into the Ambly- 

 stoma inside of six weeks, while I have had but three 

 changes of those kept in the cauf (sixty of them) in three 

 months. During that time they have not been fed at all. 

 The Siredon mexicanus is said to never undergo the 

 transformation in its home, and Professor Marsh doubts 

 that it ever makes it here. This doubt I can put at rest. 

 They do make the change here, and in large numbers. 

 During the latter part of the month of July and the en- 

 tire month of August, if the day is rainy or misty, they 

 come from the lake to the shore in large numbers, and 

 secrete themselves under some piece of wood or rock 

 where they can keep moist. Sometimes they venture out 

 in a shower, and the sun catches them before they can 

 obtain shelter either in the lake or under cover, and in a 

 few minutes kills them. They can be found dried hard 

 anywhere about the lake, on the shore or in the grass. 

 While catching Siredon I have seen and caught a num- 

 ber of Amblystoma in the lake, with the metamorphosis, 

 as far as I could see, as complete as those we find half a 

 mile from the lake. They cover the ground by thousands 

 during a warm summer rain, coming Irom every conceiv- 

 able place where they could have found shelter, from 

 under rocks, boards, old ties, and out of gopher holes. I 

 have a cat that eats them greedily. She has fished sev- 

 eral out of jars on the table and devoured them during 

 the night when there was no one to watch her ; and 1 

 am told by a resident that the numerous skunks that live 

 around the lake live principally on them. They are of 

 two colors, a blackish green and a yellowish green color. 

 I have had two of the blackish green complete the 

 change in sequence, while one of the yellowish green was 

 completing it under the same circumstances of change of 

 water and food. I think this will be found to be the re- 

 sult in all similar cases. I have caught them in all 

 stages of growth and in all stages of their changes into 

 the Amblystoma state. During the months of July and 

 August they lie close to the shore of the lake, where it is 

 shallow; but after the first frost they disappear com- 

 pletely, or at least I have never been able to find them. I 

 think they must bury themselves in the mud at the bot- 

 tom of the lake, as I have stirred up the grass often and 

 have not seen them issue from it. 



AN ANALYSIS OF WATER DESTRUCTIVE TO 

 FISH IN THE GULF OF MEXICO. * 



BY F. M. Endlich. 



Having completed the examination of sea-waters from 

 the Gulf of Mexico, so tar as the scant supply would per- 

 mit, I have the honor to offer the following report there- 

 upon, the water in which the fish die being designated 

 as A, the good water as B : 



A. B. 



Specific gravity 1.024 1.022 



Solid constituents (total), per cent. . . 4.0780 4.1095 



Ferric compounds, per cent 0.1106 0.0724 



Injurious organic n atier ratic=3 ratio=2 



I find that the water A contains a large quantity of 

 Alga and infusoria. It is eminently probable that the 

 former may have had an injurious effect upon the fish. 

 Specimens of the algas have been submitted to Professor 

 Goode, who will send them to some expert, in order that 

 their specific gravity may be determined. 



The " dead fish " in possession of the United States 

 National Museum are such that any examination of the 

 organs of respiration will be of no avail. 



I cannot find, even by spectroscopic analysis, any min- 

 eral constituents in the water A which could noxiously 

 affect the fish. 



In my estimation the death offish was caused by the 

 more or less parasitic algae, which are found in large 

 quantities in water A, but do not occur at all in water B. 



In case the same phenomenon should recur, the pres- 

 ence of an expert in the questions involved, more partic- 

 ularly chemistry and botany, would most likely lead to 

 definite results, 

 Prof. S. F. Baird, 



Secretary the Smithsonian Institute, 

 Washington, D. C. 



A MICROSCOPICAL STUDY OF THE IRON ORE, 

 OR PERIDOTITE OF IRON MINE HILL, 

 CUMBERLAND. RHODE ISLAND.f 



By M. E. Wadsworth. 



The attention of the writer was first particulady called 

 to this formation by some specimens presented to him 

 by Mr. H. B. Metcalf in the Spring of 1880. These 

 did not appear to the writer to be any common ore of 

 iron, but rather fragments of a basic eruptive rock con- 

 taining much iron. Sections were accordingly made 

 which revealed its true character. 



The formation was described by Dr. Charles T. Jack- 

 son in his report on the Geological Survey of Rhode 

 Island in 1840. He states that Iron Mine Hill " is a 

 mountain mass of porphyritic magnetic iron ore, 462 feet 

 in length, 132 feet in width, and 104 feet in height above 

 the adjoining meadow. From these measurements, 

 which were made over only the visible portion of this 

 enormous mass of iron ore, it will appear that there are 

 6,342,336 cubic feet of the ore above natural drainage. 

 . . . Its specific gravity is from 3.82 to 3.88. . . .This ore is 

 remarkable both on account of its geological situation 

 and its mineralogical and chemical composition. It ap- 

 pears to have been protruded through the granite and 

 gneiss at the same epoch with the elevation of numerous 

 serpentine veins which occur in this vicinity. This will 

 appear the more probable origin of this mass, when we 

 consider its chemical composition in comparison with 

 that of the iron ore, which we know to have been thrown 

 up with the serpentine, occurring on the estate of Mr. 

 Whipple, and the fact that the ore at Iron Mine Hill is 

 accompanied by serpentine mixed with its mass in every 



* From the Proceedings of United States National Museum. 



+ From the Bulletin 0/ The Museum Comparatixie of Zoology. — Har. 

 vard College. 



