56 



NA TURE 



{^Mov. 18, i! 



ous facts bearing upon it have been announced in its 

 reports and bulletins. 



(6) The work of increasing the supply of valuable fishes 

 and other aquatic forms in the waters of the United States, 

 whether by artificial propagation or by transplantation, 

 although very successful, may be considered as yet in its 

 infancy. 



It must be remembered that the agencies which have 

 tended to diminish the abundance of the fish have been at 

 work for many years and are increasing in an enormous 

 ratio. This, taken in connection with the rapid multipli- 

 cation of the population of the United .States, makes the 

 work an extremely difficult one. If the general conditions 

 remained tlie same as they were fifty years ago, it would 

 be a very simple thing to restore the former equilibrium. 



At that time, it must be remembered, the methods of 

 preservation and of wholesale transfer, by means of ice, 

 were not known, while the means of quiclc transportation 

 were very limited. Hence a small number of fish sup- 

 plied fully the demand, with the exception, of course, of 

 species that were salted down, like the cod, the mackerel, 

 and the herring (including the shad). Now, however, the 

 conditions are entirely changed. The whole country par- 

 ticipates in the benefits of a large capture of fish, and 

 there is no danger of glutting the market, since any sur- 

 plus can be immediately frozen and shipped to a distance, 

 or held until the occurrence of a renewed demand. 



Another impediment to the rapid accomplishment of the 

 desired result is the absence of concurrent protective 

 legislation of a sufficiently stringent character to prevent 

 unnecessary waste of the fish during the critical period of 

 spawning, and the erection or maintenance of impediments 

 to their movements in reaching the spawning-grounds. 

 This is especially the case with the shad and the salmon, 

 where the simple construction of an impassable dam, or 

 the erection of a factory discharging its poisonous waste 

 into the water, may in a few years entirely exterminate a 

 successful and valuable fishery. 



It is to be hoped that public opinion will be gradually 

 led up to the necessity of action of the kind referred to, 

 and that year by year a continued increase in the fisheries 

 will be manifested. Even if this does not occur as rapidly 

 as some may hope, the experiments so far furnish the 

 strongest arguments in favour of continuing the work for 

 a reasonable time. A diminution that has been going on 

 for fifty or more years is not to l)e overcome in ten, in view 

 of the increasing obstacles already referred to. 



Among the species an increase of which in their appro- 

 priate places and seasons is to be hoped for, in addition 

 to those now occupying the attention of fish-culturists, are 

 the cod, the halibut, the common mackerel, the Spanish 

 mackerel, the striped bass, or rockfish, &c. 



One of the most important, and at the same time among 

 the most promising, fish is the California trout, with which 

 it is hoped to stock large areas of the country. Its 

 special commendations are mentioned elsewhere in this 

 Report. 



Another fishery earnestly calling for assistance, and 

 capable of receiving it, is that of the lobster, the decrease 

 of which has been very marked. The experiments of the 

 Fish Commission suggest methods by which the number 

 can be greatly increased. Something, too, may be done 

 with the common crab of the .Atlantic coast and its 

 transfer to the Pacific. Some kinds might also be ad- 

 vantageously brought to the eastern portion of the United 

 States from the Pacific coast and from the European 

 seas. 



A subject of as much importance as any other that now 

 occupies the attention of the Fish Commission is an in- 

 crease in the supply of oysters. In no department of the 

 American fisheries has there been so rapid and alarming 

 a decrease, and the boasted abundance of this mollusk on 

 the Atlantic coast, especially in Chesapeake Bay, is rapidly 

 being changed to a condition of scarcity which threatens 



practical extermination, as is almost the case in England 

 A fishing industry producing millions of dollars is menaced 

 with extinction, and needs the most stringent measures far 

 its protection. 



The U.S. Fish Commission has been very fortunate, 

 through its agents and assistants, in making important 

 discoveries in connection with the propagation of the 

 oyster, which are referred to hereafter in this Report ; and 

 it is proposed to establish several experimental stations for 

 applying the discoveries thus made, so as to constitute a 

 school of instruction and information to persons practi- 

 cally engaged in the business. 



There are other shell-fish besides the oyster that will 

 well repay the trouble of transplantation and multiplica- 

 tion. Among these are several species of clams belong- 

 ing to the Pacific coast of the United States, which are 

 much superior in size, in tenderness, and in excellence of 

 flavour to those on the eastern coast. Most of these are 

 natives of Puget .Sound, and the completion of the Nor- 

 thern Pacific Railway is looked forward to as a convenient 

 means of transferring them to Eastern waters. The 

 common clams of the Atlantic coast are also fair subjects 

 of experiment. 



VOLCANIC DUST FROM NEW ZEALAND 

 A SHORT time since. Sir Julius von Haast sent me a 

 -^*- small packet of volcanic dust from New Zealand, 

 and requested me to examine it. The dust fell on June 10 

 of the present year (the day of the Tarawera eruption) 

 at Matakava, Hicks Bay, 115 miles from the scene of the 

 eruption. This dust is very fine, and, when regarded in 

 the mass, is a dull, darkish gray colour. When examined 

 under the microscope, it may be divided into — 



((() Bits of a more or less scoriaceous aspect — tiny 

 lapilli, commonly almost opaque, being only translucent 

 on thin edges — consisting of a somewhat brownish glass 

 containing much disseminated ferrite. With reflected 

 light they are a light to a darkish gray in colour, some- 

 times slightly reddish or brownish, with moderately rough 

 surfaces. In size they usually vary from about '005 to 

 ■008 inch in the longest diameter ; the former being the 

 more common measurement ; the latter is but rarely ex- 

 ceeded, the largest fragment in the portion which I have 

 examined being 012 inch in diameter ; lapilli also occur 

 of less than '005 inch. 



(b) Chips, more or less transparent, generally not e.'c- 

 ceeding "005 inch in diameter, and of all dimensions 

 downwards to the finest dust. The majority of these 

 chips are glass, commonly quite colourless ; some of them 

 contain bubbles, spherical, spheroidal, or more or less 

 cylindrical. Sometimes these are quite '001 inch in 

 longest diameter. Many chips show a ridgy surface, and 

 are evidently formed by the destruction of a very frothy 

 pumice like that of Krakatab. Some of the glass is of a 

 light brown colour ; occasionally it contains microliths of 

 feldspar or trichites. The mineral chips are much less 

 numerous than those of glass ; the great majority of them 

 are feldspar. Many of these are flat flakes apparently 

 detached from a basal plane, but a few e.\hibit twinning. 

 Some may be sanidine, but a plagioclastic feldspar is 

 certainly present. The chips, however, are ill-suited for 

 optical measurements, and the results which I have 

 obtained are rather discordant. So far as I can come to 

 a conclusion, I should say that the extinction-angles seem 

 to indicate the not unfrequent presence of a feldspar which 

 belongs rather to the oligoclase-albite group than to the 

 labradorite-anorthite. I find very few indications of the 

 presence of a pyroxenic constituent. One or two frag- 

 ments are a greenish hornblende ; three or four in general 

 appearance resemble small flakes of magnesia-iron mica — 

 lying on their basal faces, but some of these show dichroism, 

 and only extinguish in certain positions between crossed 

 Nicols, so that they cannot be this mineral. As to 



