Swift Streams Research Articles

Three Early Water-Powered Mills in Northwest Greene County, Ohio, and Their Impacts on the Landscape

Three Early Water-Powered Mills in Northwest Greene County, Ohio, and Their Impacts on the Landscape David Nolin (bio) After the Treaty of Greenville in 1795, settlers rapidly made new settlements in what is now Greene County, Ohio.1 One of the first priorities for the many new towns that began in this forest and prairie wilderness was the development of water-powered mills, small industries that utilized the constant and reliable energy source of falling water to provide vital services. This ancient technology was already heavily utilized in the eastern United States, and as new lands were settled, mills were quickly built to meet the needs of new communities.2 Millwrights, experts in the craft of constructing mills and conveying water to them, typically designed and built the mills, and millers operated them as a business. These early mills provided many services, but two of the most common and essential were sawmills and gristmills. Sawmills facilitated the conversion of trees from the hardwood forests that covered much of the land into lumber for building materials. Early sawmills were typically small operations run by one or two people. A frame containing one or more vertically mounted saws was attached to a crank, which was turned by a waterwheel. These mills could cut about 3,000 feet of lumber in a working day, some 20 to 25 times more efficient than two men working in [End Page 51] a saw pit and using a whipsaw.3 The first sawmill appeared in Ohio in 1789, and by 1840, there were 2,883 of them operating in the state. A thorough examination of early Ohio sawmills was published in the Ohio History journal in 1975.4 Click for larger view View full resolution Location of eighteenth-century mills and millraces on Hebble Creek, Bath Township, Greene County, plotted on USGS topographical map. The first gristmill appeared in Ohio in 1790, and by 1840, there were 1,861 of them in Ohio, providing the vital service of grinding grain harvested from agricultural fields between two round millstones, converting it to flour for bread and other staples.5 In early mills, a vertical waterwheel powered one or more sets of millstones or “buhrs” that could grind 10 to 12 bushels of grain per hour.6 After 1860, many gristmills replaced their vertical waterwheels with more efficient turbines. By the 1880s, most millstone systems were being [End Page 52] replaced by a new innovation, the roller system, using steel or ceramic cylinders that ground the grain against a flat plate. Roller mills had the ability to separate the bran from the germ, allowing the collection and sale of white flour. By the 1900s, the availability of engines powered by inexpensive fossil fuels eliminated the need for water power and the upkeep of water-wheels, millponds, and millraces, and many water-powered mills that could not compete were abandoned. The number of water-powered gristmills in Ohio dropped from 1,181 in 1870 to 94 in 1922.7 A comprehensive study of Ohio gristmills, their technological evolution, their rapid increase on Ohio streams, and their subsequent decrease was thoroughly examined in Water-wheels and Millstones: A History of Ohio Gristmills and Milling. The first step for an early millwright was to identify a location or “seat” where the proposed mill could be successful.8 A seat required that a steady flow of water be available that could be conducted to the mill. A millpond was usually established upstream of the mill where a valley contained a natural constriction that could be impounded by a dam made of wood and/or stone.9 The raised water level provided the stored energy to power the mill. Water was diverted from the millpond by a head race, a dug channel, or a wooden trough that conveyed the water to a waterwheel, which turned the mill machinery. After turning the waterwheel, the water was sped back to the source stream via a dug channel called a tailrace. On a relatively swift stream, the head races and tailraces could be quite short, and these streams were the most favorable for mills. For instance, between 1798 and 1875, 11 gristmills, five sawmills, and...

Revisiting the Timing and Events Leading to and Causing the Johnstown Flood of 1889

The Johnstown Flood of May 31, 1889, was responsible for more recorded deaths than any other disaster in the United States until the Galveston hurricane of 1900.1 An important difference between the two is that the Johnstown flood was not a natural disaster. Although the Johnstown region was in the midst of a particularly wet spring and the former boroughs that now form the city of Johnstown were already experiencing low-level flood-ing on May 31, the ultimate reason for the high death toll was the catastrophic failure of the South Fork Dam, located fourteen miles upstream from the outskirts of Johnstown on the South Fork of the Little Conemaugh River (see fig. 1). The millions of tons of water released by the failure of the dam caused devastation along the Little Conemaugh River drainage. As the water moved downstream it was temporarily impounded by debris dams behind two Pennsylvania Railroad bridges (Viaduct and Bridge no. 6), which caused "reformation of the lake" at these points. When Bridge no. 6 failed, the rejuvenated flood wave sped toward Johnstown. Most structures

The 2002 flood consequences in the catchment of Otava River, Czech Republic

In this article we analyse and compare the data on consequences of the catastrophic 2002 floods in two subcatchments of Otava river basin collected during specialized mapping in 2003. The Otava River is situated in the southwest of the Czech Republic. From its basin we have chosen two different subcatchments: Lower Otava River, surrounded by flat, lowland landscape and Losenice River, swift stream descending from the Sumava Mountains. We also present some basic data on the flood course and its hydrological parameters and meteorological causes.

Here's Something Now, and: The Famous Dream of Sergius P., and: Lost Rudiments

Here's Something Now Songbird outside my window says: "Sweet enough. Sweet enough. Sweet, sweet, sweet." The artist's model, a florist from town, reclines on a broad window sill, facing the garden. Old sycamores, a sleeping owl, a neighbor tending his yard. From a distance, say where deer lie in shadows of tulip trees, she may seem a bowl of peaches, still life of terracotta, thatch and flowers. How much secret beauty there is in the world. There is the traveler in the tale who grew cold and sleepless on a stranger's couch, his spirit, thin. Who went barefoot and shaking to her bedroom door. If this were fiction, he might enter and be warmed. Might huddle next to her, her body kindling his heart and his groin. Might reach for her as if he cannot help himself. In such circumstances giants, heroes and others generously blessed may be overcome by sorrow. Might even ask their hearts to stop beating for the sake of the story. [End Page 90] On the first night home from his journey, a man looks at his wife on the other side of the bed. She has shaved her pudendum. She is weeping. What is the question here, and which of us will ask it? The Famous Dream of Sergius P. White wolves in the walnut trees and fresh cowflop to heal the princess' eczema. Miracle that a thousand sacks of rice fly after my darling in a flock, like geese. I have not slept in weeks for living in a fairytale; a neighbor wife is bending naked by a pool, the thief of peace. Call out the swan boats! Mine is the voice of Sancho Panza, pleading to be made governor of some small island. Or some bit of sky. In my tale the means of entry and escape is a small place in the wall disguised by watercress where a brook runs through. Clothe me in thrushes feathers. I will make a sound and call it singing. I will sigh, and call it prayer. [End Page 91] Lost Rudiments – for Nan Oslund Farady1942–1996 There was an ocean, everywhere. There was a turtle 12 feet long. No wonder stories linger of how the world began. Like fossils in arroyos of our songs. Outside the bitter river live horse-footed men. And infants, born clutching milky stones. There sits a man with a lion beside him. Giant fish swim through the trees. I come there sometimes in my heart to listen for your voice. St. Joseph of Cupertino, the aerial saint; you said he loved the Blessed Virgin, and so could fly, easy as Beryl Markham in her white silk blouse. The door of the temple is closed today, for there is war. I wonder if you see the tops of everything. And whether you look back to see yourself, asleep. Do you see how empty is this room where I sit by a window under stars, awake. The pond asleep, the endless mountains dark. Five million years ago on a bright morning, our kinfolk picked up pointed sticks and moved across the savannah from a dry lake toward a swift stream they had heard of. [End Page 92] Odor of sweat and dead fish filled their nostrils. A dollar was worth nothing. They had their sacred post, they were alive, and that was surely something as long as it lasted. They would not imagine, as you did, David Hume at prayer. Or Frollo the archdeacon falling from Notre Dame. Or us, teaching metal to fly and plastics to sing because we learned how. Do you know our hearts, you who are sky-clad now?

The function of the suckers of larval net‐winged midges (Diptera: Blephariceridae)

1. Larval net‐winged midges (Diptera: Blephariceridae) possess six ventral suckers that enable them to inhabit swift streams. Each sucker consists of a suction disc and a cavity with a piston. Large muscles are inserted within the piston, as well as at the base of the suction disc. This structure infers that both attachment and release of the sucker is achieved by vertical movements of the piston.2. Live observations of blepharicerid larvae revealed that the sucker is indeed attached by an upward movement of the piston, but that the cavity is flooded when the sucker is released. The piston is lowered only at the end of a sucker ‘step’, expelling water from the cavity.3. During foraging, the maxilla and the piston of the first sucker are moved synchronously, indicating that the first sucker functions as a holdfast thus facilitating grazing.4. The adhesive forces, as well as the relative size of blepharicerid suckers, differ amongst species. They are highest in Hapalothrix lugubris and lowest in Liponeura cordata, which correlates with the hydraulic stress to which the larvae of these species are exposed in their preferred habitat. The balance between the efficiency of their retention structure and the hydraulic conditions of their preferred habitat defines a key dimension of their ecological niche.

Spatial niche variability for young Atlantic salmon (Salmo salar) and brown trout (S. trutta) in heterogeneous streams

Abstract–Habitat is important in determining stream carrying capacity and population density in young Atlantic salmon and brown trout. We review stream habitat selection studies and relate results to variable and interacting abiotic and biotic factors. The importance of spatial and temporal scales are often overlooked. Different physical variables may influence fish position choice at different spatial scales. Temporally variable water flows and temperatures are pervasive environmental factors in streams that affect behavior and habitat selection. The more frequently measured abiotic variables are water depth, water velocity (or stream gradient), substrate particle size, and cover. Summer daytime, feeding habitats of Atlantic salmon are size structured. Larger parr (>7 cm) have a wider spatial niche than small parr. Selected snout water velocities are consistently low (3–25 cm. s−1). Mean (or surface) water velocities are in the preferred range of 30–50 cm. s−1, and usually in combination with coarse substratum (16–256 mm). However, salmon parr demonstrate flexibility with respect to preferred water velocity, depending on fish size, intra‐ and interspecific competition, and predation risk. Water depth is less important, except in small streams. In large rivers and lakes a variety of water depths are used by salmon parr. Summer daytime, feeding habitat of brown trout is also characterized by a narrow selection of low snout water velocities. Habitat use is size‐structured, which appears to be mainly a result of intraspecific competition. The small trout parr (<7 cm) are abundant in the shallow swift stream areas (<20–30 cm depths, 10–50 cm. s−1water velocities) with cobble substrates. The larger trout have increasingly strong preferences for deep‐slow stream areas, in particular pools. Water depth is considered the most important habitat variable for brown trout. Spatial niche overlap is considerable where the two species are sympatric, although young Atlantic salmon tend to be distributed more in the faster flowing and shallow habitats compared with trout. Habitat use by salmon is restricted through interspecific competition with the more aggressive brown trout (interactive segregation). However, subtle innate differences in behavior at an early stage also indicate selective segregation. Seasonal changes in habitat use related to water temperatures occur in both species. In winter, they have a stronger preference for cover and shelter, and may seek shelter in the streambed and/or deeper water. At low temperatures (higher latitudes), there are also marked shifts in habitat use during day and night as the fish become nocturnal. Passive sheltering in the substrate or aggregating in deep‐slow stream areas is the typical daytime behavior. While active at night, the fish move to more exposed holding positions primarily on but also above the substrate. Diurnal changes in habitat use take place also in summer; brown trout may utilize a wider spatial niche at night with more fish occupying the shallow‐slow stream areas. Brown trout and young Atlantic salmon also exhibit a flexible response to variability in streamflows, wherein habitat selection may change considerably. Important topics in need of further research include: influence of spatial measurement scale, effects of temporal and spatial variability in habitat conditions on habitat selection, effects of interactive competition and trophic interactions (predation risk) on habitat selection, influence of extreme natural events on habitat selection use or suitability (floods, ice formation and jams, droughts), and individual variation in habitat use or behavior.

Population variation in spawning current speed selection in the blacktail shiner,Cyprinella venusta (Pisces: Cyprinidae)

Many stream fishes lay demersal eggs. Some species simply scatter the eggs across the substrate, but many place the eggs in protected sites such as crevices (e.g., Cyprinidae:Cyprinella). Eggs laid in crevices may experience increased development times or lower embryo survival due to reduced water exchange rates compared to more open egg deposition sites. If so, the presence of an appreciable current near the crevice may be important for insuring water exchange. However, currents that are too strong may prevent complete insemination or prevent the eggs from adhering to the substratum before they are washed from the crevice. Thus, current speed preferences for spawning may be under strong stabilizing selection. Representatives of four populations of a crevice spawning stream fish (blacktail shiner,Cyprinella venusta), representing environments ranging from a swift stream to a lake, were studied in stream tanks to evaluate female spawning current use. The observed frequency of use of spawning currents was significantly different from random in all populations. Low current speeds were generally avoided, and a speed of ca. 30 cm sec−1 was used most often. However, significant differences were observed among populations, and the variation correlated well with the apparent range of current speeds found in the four environments. Although other possible explanations cannot be dismissed, the results are consistent with the hypothesis that the populations have become adapted to their local current regimes.

A Contribution to the Life History of the Blueback Herring, Alosa aestivalis

Blueback herring (Alosa aestivalis) were first detected near the mouth of the Connecticut River on April 13, 1966, April 18, 1967, and April 19, 1968, when water temperatures were 7.8, 4.7, and 9.4 C, respectively. Spawning was first observed when stream temperature was 14 C. Abundance in the river was greatest from mid-May to mid-July, but smaller spawning groups were observed in late April and mid-September. Blueback herring preferred a swift stream flow and hard substrates for spawning sites, and to a great degree were spatially isolated from spawning alewives. Both sexes were present in age classes III through VII; age V was the modal class for each sex. In the spawning areas there was a 2:1 sex ratio of males to females. Males were more abundant in age classes III, IV, and V; there was equal abundance in age class VI, but females dominated age class VII. Fecundity was related to total fish length up to about 300 mm, but declined in larger females.

Quelques Trichoptères Philopotamidae de France et d'Algérie

SummaryF. Vaillant: Some Trichoptera Philopotamidae from France and Algeria.There are only three species of Philopotamus in continental France and specimens of each show very little difference between them; their larvae live under stones in swift streams and torrents.Quite to the contrary, Wormaldia, with five species occuring in France, comprises many subspecies and varieties of these. This is probably due to geographical isolation, for larvae of most populations of Wormaldia develop in shallow springs. Dolophilus larvae are also crenobiontic and the species of this genus, may be to a smaller extent than those of Wormaldia, have been submitted to microendemism.One new species of Wormaldia, 7 new subspecies of Wormaldia and of Dolophilus and 4 varieties of Wormaldia occipitalis occipitalis are described.

Illegitimacy, Sexual Revolution, and Social Change in Modern Europe

Illegitimacy, Sexual Revolution, and Social Change in Modern Europe Sexuality in traditional society may be thought of as a great iceberg, frozen by the command of custom, by the need of the surrounding community for stability at the cost of individuality, and by the dismal grind of daily life. Its thawing in England and Western Europe occurred roughly between the middle of the eighteenth and the end of the nineteenth centuries, when a revolution in eroticism took place, specifically among the lower classes, in the direction of libertine sexual behavior. One by one, great chunks-such as premarital sexuality, extraand intra-marital sexual styles, and the realm of the choice of partners-began falling away from the mass and melting into the swift streams of modern sexuality. This article considers the crumbling of only a small chunk of the ice: premarital sexuality among young people, studied from the evidence of illegitimacy. However, in other realms of sexuality, a liberalization was simultaneously in progress. There is evidence that masturbation was increasing in those years. The first transvestite appears in Berlin police blotters in 1823. Prostitution in Paris tripled in the first half of the nineteenth century. And, between 1830 and I855, reported rapes in France and England climbed by over 50 per cent.' It is not the concern of this paper, however, to pin down qualitatively these other developments. This is a task reserved for future research based upon a

Thermal Selection in Tadpoles of the Tailed-Frog, Ascaphus truei

Tadpoles of the tailed-frog, Ascaphus truei, exhibit distinct responses to temperature when placed in laboratory temperature gradients. Thermo-regulatory behavior is evidenced by an avoidance of temperatures above 22 C. Both first and second year tadpoles select over a wide temperature range (0-22 C), but first year animals tend to congregate below 10 C, whereas second year tadpoles aggregate above 10 C. Thermal acclimation had little influence on the preferendum of either year class, but photoperiod may alter the response of second year tadpoles to a temperature gradient. INTRODUCTION Extensive comparative studies with fish and reptiles have illustrated that many of these poikilotherms have a characteristic range of temperatures (the thermal preferendum) in which they tend to regulate body temperatures by behavioral selection. Despite the importance of such behavior in the ecology of these poikilotherms, there is only scant information concerning thermoregulation in amphibians, particularly larval forms. With little experimental background, Brattstrom (1963) suggested that amphibians behaviorally seek microhabitats of optimal temperatures and avoid deleterious thermal extremes. Some indication of temperature preference in anuran tadpoles can be derived from field observations and tadpoles of several species appear to aggregate at specific temperatures in ponds (Brattstrom, 1962). The host of variables encountered in natural habitats, obfuscate the response of an organism to temperature. Temperature selection in amphibian larvae, under controlled laboratory conditions, has been reported in only four species of anurans (Workman and Fisher, 1941; Herreid and Kinney, 1967; Lucas and Reynolds, 1967) and two species of urodeles (Licht and Brown, 1967; Lucas and Reynolds, 1967). The anuran, Ascaphus truei, was selected for this study because of its proposed primitive position in amphibian evolution; all previous work with anuran tadpoles has been conducted with ranid species. Much of the literature concerned with Ascaphus suggests that the distribution of this species may be primarily dependent on low temperatures; these ideas stimulated questions of how the tadpoles of this species would behave in response to temperature. Various aspects of the life history of A. truei have been previously documented (Gaige, 1920; Noble and Putnam, 1931; Slater, 1931; Ricker and Logier, 1935; Metter, 1964; Bury, 1968). This species occurs chiefly west of the Cascade Mountains from southwestern British Columbia to Mendocino Co., California; it also occurs in the Rocky Mountains of Idaho and Montana and the extreme southeastern portion of Washington and in northeastern Oregon. Records of collection sites indicate that the distribution of Ascaphus is governed by requirements for perennial, swift streams of low temperature to which many aspects of its morphology and life history can be correlated (Bury, 1968). The main objective of the present study was to ascertain whether the tadpoles of Ascaphus exhibited behavioral thermoregulation; this was tested by studying the animals in laboratory thermal gradient chambers. Preliminary field observations were undertaken to ascertain the role of this behavior in the ecology of this species.

Aquatic Bryophytes as Indicators of Uranium Mineralization

Aquatic Bryophytes as Indicators of Uranium Mineralization

Laterotrema cascadensis sp. n. (Trematoda: Stomylotrematidae) from the Dipper, Cinclus mexicanus

A new species of trematode, Laterotrema cascadensis (Stomylotrematidae) from the small intestine of the dipper, Cinclus mexicanus unicolor Bonaparte, is described. It is characterized by a relatively small acetabulum, confinement of uterine slings to the posterior part of the body, and loca- tion of the genital pore at the level of the posterior part of the oral sucker. The new species was found in 10 of 13 dippers from streams of the lower Columbia River Gorge in Oregon, and also was found in this species of bird in Washington. A key to the species of the genus is presented. The small intestines of 10 of 13 dippers, Cinclus mexicanus unicolor Bonaparte, col- lected by one of us (G.L.S.) from nine swift streams of the lower Columbia River Gorge, Multnomah County, Oregon, were found to be infected with 441 trematodes of the genus Laterotrema Semenov, 1927. Also three speci- mens were recovered from this species of bird at a mountain stream about 30 miles north of Stevenson, Washington. None was found in six dippers collected along the Nehalem River, Tillamook County, Oregon. Until now seven species of Laterotrema have been described. A study of the specimens from Oregon and Washington indicated that on the basis of a relatively smaller acetabulum, confinement of the uterine slings to the pos- terior part of the body, and the location of the genital pore at the level of the posterior part of the oral sucker, they represented a new species here designated Laterotrema cascadensis.

A Possible Recycling Mechanism in Tropical Forrest

The abundance of noterid beetles in root mats along many miles of swift streams in Columbia suggests that they play a role in carrying nutrients back into the surrounding forests.

The Fishes of Blue River in Oklahoma with Descriptions of Two New Percid Hybrid Combinations

The fishes of Blue River in Oklahoma have received very little attention from ichthyologists. The early collectors apparently by-passed Blue River completely. Paden (1948) reported Microperca (- Etheostoma, in part) microperca (Jordan and Gilbert) from Thomas Bricken Spring, a tributary of Blue River and Hubbs and Bonham (1951) reported Notropis blennius (Girard) from the same locality. Moore and Rigney (19,52) described Poecilich,thys (=Etheostoma, in part) radiosus cyanorum from Blue River and included some notes concerning the percid associations in the river. Since there are so few references to the fish fauna of Blue River, an annotated list seems pertinent. Two new percid hybrid combinations, collected and identified by Dr. G. A. Moore of Oklahoma Agricultural and Mechanical College, are described. The combination Etheostoma radiosum cyanorum (Moore and Rigney) X Eth,eostoma spectabile (Agassiz) subsp. was taken from Blue River 24 miles south of Ada, Oklahoma. The hybrid, Etheostoma spectabile pulchellum (Girard) X Etheostoma whipplei whipplei (Girard), is included because of the close relationship of the parental species of it and those of the above-mentioned hybrid. The latter specimen was taken from Sand Creek near Foraker in Osage County, Oklahoma. Description of the, river.-The Blue River rises in Pontotoc County, Oklahoma, about six miles west of Fittstown. It is about 100 miles long, drains an area of approximately 660 square miles and flows in a southeasterly direction through Pontotoc, Johnston and Bryan counties to join the Red River south and east of Durant. The watershed is composed entirely of gently rolling hill country, about 48 per cent of which is timbered. Elevations at the headwaters are about 1250 feet above sea level, decreasing to approximately 500 feet above sea level near the river's mouth. The average antnual rainfall varies from 37 inches at the headwaters to 40 inches at the lower end of the basin. The overflow area is rather narrow and, in the lower 60 miles of the river, approximately 12,000 acres are subjected to overflow annually (Anon. 1936). The Blue River is a clear and moderately swift stream with an average gradient of about 7.5 feet per mile. The native vegetation of the entire watershed is a typical oak-woods association. List of collections.-The collections, with dates and localities, are given in chronological order and are followed by a description of collection stations.

Wordsworth's River Duddon Sonnets

Because none of Wordsworth's later poems has been so neglected as his sonnet cycle The River Duddon, the pleasant task remains of doing it critical justice. O. J. Campbell has used it as an illustration of Wordsworth's later symbolic art, and the geographical features of the landscape through which the Duddon flows have been adequately described. Furthermore, the English river is a happier symbol than the deer in The While Doe of Rylstone and has simpler, more natural virtues than the mystic Holy River which is the life-stream of pure religion in the Ecclesiastical Sonnets. Most of the Duddon poems, it is true, fall less sublimely upon the ear and have less nobility and perfection than the finest he composed before 1806. Even so, their level is consistently high, part of their attractiveness being a sometimes bleak austerity. In several ways too, as Wordsworth generously says in his “Postscript,” the sequence is related to Coleridge's project, The Brook, outlined in Biographia Literaria. More important, however, is the final development of an extended theme based upon water imagery, for after 1797 Wordsworth's profoundest insights are often associated with it. We have also Robert Arnold Aubin's comment that “the greatest river-poem of all is Wordsworth's River Duddon (1820)… . With its use of apostrophe, local pride, historical reflection, catalogue, moralizing, genre scenes, episode, early memories, prospect, ruin-piece, and Muse-driving ( On, loitering muse—the swift stream chides us—on!'), it is not wonderful that a reviewer perceived that the work belonged in the main stream of topographical poetry.”

Norway's Industrialization

N & NORWAY, through the development of geographic features usually considered adverse, has become an industrialized nation. Located on the Arctic Circle, geographic features are ice fields covering 4 per cent of the surface of the country; many rivers of ice creeping slowly down mountain sides; snowcovered winters, and summers of abundant rainfall, with precipitation of more than 70 inches a year in some localities along the west coast. The ice, snow, and rainfall, coupled with precipitous mountains of rock, ranging from 1,500 to 6,000 feet in height, cause numerous waterfalls with a dependable flow of water. These waterfalls, as well as a number of short, swift streams, have

Migrations of Salmon

AT a meeting of the Washington Academy of Sciences held recently, a discussion on: the homing migrations of salmon was opened by Prof. Henry B. Ward. According to a report by Science Service, of Washington, D.C., he said that the return of salmon, generation after generation, to their ancestral breeding grounds, is a response to definite stimuli, amongst which he regards temperature as being the most powerful. Swiftness of current has also some effect in guiding the fishes, although relative acidity of the water seems to have no influence. But if it be admitted that salmon return to the streams where they were born—and there is much evidence supporting that view—it cannot be admitted that either the temperature of a particular stream or the swiftness of its current remains constant. It is difficult to understand, therefore, just how these variable factors can guide migrating salmon, not to a specially cold or swift stream, but to a particular stream the one outstanding character of which is that they were born there.

The Oxygen Consumption of Ephemerid Nymphs From Flowing and From Still Waters in Relation to the Concentra-Tion of Oxygen in the Water

ABSTRACTFox & Simmonds (1933) and Fox et al. (1935) have shown that certain may-fly nymphs, a caddis larva and an isopod from swift streams have a higher oxygen consumption than nearly related forms from still waters or slow-flowing streams. Their results were summarized in Table IV1 of Fox et al. (1935). It has since been shown by Washbourn (1936) that the oxygen consumption of trout fry reared in swiftly flowing water is greater than that of fry reared in slow water.Wolsky & Holmes (1933) found the oxygen consumptions of four individuals of the crayfish Astacus leptodactylus Eschscholtz, from Lake Balaton, to be 90, 103, 104 and 105 mg. of oxygen per kg. of animal per hour at 19–21° C., the animals weighing 16, 22, 36 and 64 g. respectively. The mean of these values for oxygen consumption is 101. Without studying the problem we are now considering, Wolsky (1934) later found that the oxygen consumptions of seven individuals of A. torren-tium (Schrank), living in a swift stream in Hungary, were 160, 188, 157, 157, 170, 102 and 137 mg. oxygen per kg. of animal per hour at 19–21° C., the animals weighing 8, 8, 15, 17, 17, 21 and 32 g. respectively. The mean of these values for oxygen consumption is 153. The oxygen consumption of A. torrentium is thus 50 per cent greater than that of A. leptodactylus, and the relation between oxygen consumption and weight suggests that habitat, not size, was responsible for this difference.

Oxygen Consumption of Mayfly Nymphs in Relation to Available Oxygen

LITTLE is known of the reasons why freshwater animals are confined to certain habitats, or of the effects of their particular environments on the metabolism of the animals. The first steps in a study of these questions were reported in NATURE, 130, 277 (1932). It has been shown that certain animals living in swift streams have a higher oxygen consumption and rate of heart beat than nearly related animals living in still waters, and that they are less resistant to water lacking oxygen1,2,3. The next step has been to study the oxygen consumption of such animals in terms of the available oxygen, and we have confined ourselves to mayfly nymphs. We have used Baetis scambus and Baetis sp. (the latter is one third the weight of the former) from a swift stream, Leptophlebia vespertina from Lake Windermere, Cloeon dipterum from a pond, and Ephemera vulgata living in mud in a pond. Our results are summarized in Fig. 1, in which the vertical line at an oxygen concentration of 7.9 c.c. per litre marks the oxygen content of water in equilibrium with the atmosphere at the temperature of the experiments, namely, 10°.