770 



SCIENCE. 



[N. S. Vol. III. No. 73. 



into a fence post. A number of excellent 



photographic views accompany this report. 



E. DeC. Ward. 

 Haevaed TJniveesity. 



SCIENTIFIC NOTES AND NEWS. 

 ANNUAL EEPOET OF THE GEOLOGICAL StTEVEY. 



The Fifteenth Annual Report of the United 

 States Geological Survey has just been delivered 

 by the Public Printer. It is a handsome volume 

 of 755 pages and 48 plates, and contains, be- 

 sides the administrative reports of the Director 

 himself and of chiefs in charge of work, the fol- 

 lowing special papers : 



' Preliminary Report on the Geology of the 

 Common Roads of the United States,' by Prof. 

 N. S. Shaler ; 'The Potomac Formation,' by 

 Prof. L. F. Ward ; ' Sketch of the Geology of 

 the San Francisco Peninsula,' by Andrew C. 

 Lawson ; ' Preliminary Report on the Marquette 

 Iron-bearing District of Michigan,' by Prof. C. 

 E. Van Hise, W. S. Bay ley and H. L. Smyth; 

 and ' The Origin and Relation of Central Mary- 

 land Granites,' by C. R. Keyes, with an 'In- 

 troduction on the General Relations of the 

 Granitic Rocks in the Middle Atlantic Pied- 

 mont Plateau,' by the late Prof. G. H. Wil- 

 liams. 



From these titles it is evident that the paper 

 of most popular interest is the first one, on 

 roads, by the versatile Harvard professor. He 

 treats of the history of American roads, the 

 methods of using stone in road-building, the 

 relative value of road stones, their distribution, 

 sources of supply, etc. ; and thus makes a 

 timely contribution to a subject which is re- 

 ceiving special attention in all parts of the 

 country. 



This is the last report made by Major J. W. 

 Powell as Director of the Survey, who until re- 

 cently has had charge of the work, under dif- 

 ferent organizations, for twenty-five years. 



FISH CULTURE. 



In a lecture on fish culture before the Royal 

 Institution of Great Britain, Mr. J. J. Armi- 

 stead, of the Royal Commission on Tweed and 

 Solway Fisheries, thus compares the methods 

 used in Great Britain and the United States : 



The hatching apparatus which is now chiefly 

 used in England consists of a long box, the 

 water flowing in at one end protected by a 

 water board or break water, which is simply to 

 break the current and prevent it from washing 

 away the eggs which are placed in the box. 

 It also diverts the current and sends it down 

 to the bottom of the box. The water pas- 

 ses underneath and passes out at a higher 

 level, where we have a screen of perforated 

 metal to prevent the escape of the little fish, 

 and in this box is placed the hatching ap- 

 paratus proper, that is, the trays or grilles upon 

 which the ova are deposited. The grilles now 

 in use are made of glass. We found, after try- 

 ing a variety of substances, that glass is the 

 best of anything. It gives off nothing. Wood 

 and metal we know corrode in water, and in 

 some waters some metals corrode very much, 

 and a great deal of loss has been suffered by 

 some who have used metallic trays for the pur- 

 poses of incubation. The Americans like to do 

 things, as we know, on a wholesale scale, and, 

 not content with putting a layer of eggs upon 

 the apparatus, they fill a basket, as they call it, 

 half full of eggs. Then they send a current of 

 water welling up from underneath, and of 

 course the effect is that it flows through 

 amongst the eggs, and they find that in due 

 time they hatch. I have made very careful in- 

 quiries with regard to the result of the hatching 

 of ova in this way, and I have found that the 

 Americans are quite prepared to admit that 

 they had a larger percentage of mortality in their 

 metal baskets or trays than they had when they 

 used glass grilles. They said, " We have dis- 

 carded glass grilles long ago. They are too 

 expensive." And they made use of other ex- 

 cuses. But, however, we find in practice that 

 we can get far better results from these glass 

 grilles, because, as I have said, there is nothing 

 to contaminate the ova or do them injury. The 

 trout eggs absorb any metallic matter which may 

 be in the water, and become so saturated with 

 it in course of time as to be very seriously in- 

 jured. They may not be absolutely killed at 

 the time, but it has been found that, although 

 there is only a slightly increased mortality in 

 hatching upon the metal, there is a greater 

 mortality amongst the fish afterwards. They 



