An article discussing the factors affecting the rate of growth of brown trout, detailing the research udnertaken at Wray Castle, designed to clarify the influencing factors in different waters and investigate what would be required to increase their size. The article considers factors such as alkalinity, total hardness, the presence of coarse fish in the waterbodies and competition for food. Previous work undertaken on brown trout in Ireland by other authors is reviewed. A figure showing average growth rate of brown trout in five lakes, as determined from their scales (Lough Derg, Windermere, Loch Leven, Ullswater, Haweswater).

1 Two types of apparatus for exposing insects to known concentrations of toxic gases, under controlled conditions, were constructed and are described. 2 The relative resistance of different stages of the flour beetle, Tribolium confusum Duv., to hydrogen cyanide was determined, the results being treated by Bliss's method. The order of resistance was pupa (most resistant), adult, larva, egg. The difference in resistance at different ages was found for the pupa, adult and egg. The application to all these results of Cotton's theory of the relation of rate of metabolism and susceptibility to fumigants is discussed. It is considered that this theory might hold for stages other than the egg. 3 A series of experiments was carried out to discover whether individual resistance to hydrogen cyanide was inherited. It was found that the offspring of resistant individuals were significantly more resistant than the offspring of susceptible individuals, and that this difference was maintained over several generations. 4 A considerable increase in resistance was found to occur if adult beetles were removed from their flour about an hour, instead of immediately, prior to their fumigation. The reason for this increase was not determined, but various suggestions to account for it are discussed. 5 It was noted that under certain conditions, adult beetles emitted a volatile substance which was self-toxic, and also appeared to react with cyanide. 6 The dosage-mortality curves for all the experiments are discussed and possible reasons for their apparent abnormality put forward. 7 The experiments here described, which must only be regarded as preliminary, emphasize i. The complexity of the problems arising in the study of the resistance of living organisms to toxic substances. ii. The need for carrying out such experiments under as natural conditions as possible. iii. The importance of a careful analysis of factors which affect the resistance of the organism.

Summary and ConclusionsA number of soils very high in barium have been analyzed chemically and the exchangeable bases and other constituents determined by leaching with ammonium acetate solutions. The soils contained from 0.08 to 3.74 per cent Ba0. Some of the most fertile soils contained the most barium but in these soils the barium is mainly present as barite and there is an excess of soluble calcium and magnesium over soluble barium. Most of the infertile high barium soils contained an excess of barium over sulphur and in these soils the soluble calcium and magnesium are low and nearly equalled or exceeded by the soluble barium.

Growth habit as determined from spring seedings of 28 wheat varieties was studied at eight experiment stations in the years 1934 to 1936, inclusive. Data on earliness from fall sowing and winter survival from other tests are included in order to study their relation with the degree of winterness. The varieties rank in about the same order to study their relation the the degree of winterness. The varieties rank in about the same order for degree of winterness when grown at each of the stations. Degree of winterness is not closely related to time of heading from fall seeding or to winterhardiness in the varieties studied. None of the early varieties were as hardy as most of the late ones. However, a few of the late varieties were no more hardy than earlier maturing ones.

The ether-soluble fraction of a series of samples of raw silk has been determined. It has been expressed in terms of the E. S. No., which designates the number of milligrams of ether-soluble material obtainable from a 10 g. sample of silk. The E. S. Numbers of the silks which have been investigated fall between 30 and 100. The average E. S. No. is 55. There exists no apparent relation between the E. S. No. and the nature, boil-off, tenacity, elongation, cohesion and resistance to friction of raw silk. The wetting properties of raw and dewaxed silk have been compared by means of the sinking test. It was found that in general removal of the wax reduces the sinking time from many seconds or even several minutes to a fraction of a second.

Yarn friction is of considerable importance in the manufacture and conversion of all types of yarns and threads. It is indicative of the value of softening and lubricating compounds, of dyestuffs and chemicals, and also of the influence of sizing upon the yarn. Furthermore it indicates the effect of flyers, tension devices, and other guiding parts of machinery in roughening up the yarn. In order to determine the coefficient of friction of yarns and thus to get knowledge of the running quality of threads, an apparatus has been developed whereby a yarn is lifted under precision conditions until a standard rider placed upon the yarn begins to travel. At this point the angle of inclination is read on a protractor and from this the coefficient of friction of the yarn is determined simply and quantitatively.

Oat varieties were subjected to different temperatures for various lengths of time. It was determined that a temperature of 48 1/2 degrees to 52 degrees C for a period of 45 minutes would give results indicating differences in heat resistance of oat varieties. The plants tested were in the five-leaf stage. Experiments were conducted on more than 25 varieties. It was found that varieties differ widely in their ability to resist heat. Varieties adapted to the South and that are resistant to cold and have at least a partial or intermediate winter growth habit showed the greatest resistance to heat. Red oats (Avena byzantina) as a group were not more heat resistant than many varieties of A. sativa. Some varieties belonging to both species were heat resistant. Heat resistance apparently is not correlated with time of maturity, with resistance to any of the major oat diseases, with after-harvest dormancy, or with any of the observed morphological characters of the oat kernel.

Greenhouse studies were made by growing two crops of sagrain on 12 different soils, representing four samples of Susquehanna, Ruston, and Orangeburg fine sandy loams. The available P(2)O(5) in each soil, which had received different phosphate treatments, was determined by the Truog method. Susquehanna fine sandy loam, a poor soil in the field, gave as high yields in the greenhouse as Ruston and Orangeburg fine sandy loams, two excellent agricultural soils. All of the soils studied in the greenhouse contained less than 6 ppm available P(2)O(5), and 11 of the 12 responded to the first phosphate applications, but none responded to heavier applications. Sagrain yielded as well on soils with 10 ppm available P(2)O(5) as on those with 40 ppm. Maximum yields were obtained on many soils with only 8 ppm (16 pounds per acre) available P(2)O(5). Field studies were made by growing cotton on 10 different soils for five years. Soil samples were obtained from the 4-8-4 and 4-0-4 treated plats and available P(2)O(5) was determined by the Truog method. The 10 soils varied greatly in their response to phosphorus. Those containing less than 6 ppm available P(2)O(5) gave excellent response; those containing from 6 to 15 ppm gave some response; but those containing more than 15 ppm gave very little or no response to phosphorus, although available P(2)O(5) was greatly increased by the phosphate application. Cotton and sagrain failed to respond to phosphate applications on soils containing 15 ppm or more available P(2)O(5), which indicates that under southern conditions crops do not require large quantities of phosphorus. Most southern soils do not contain 15 ppm available P(2)O(5) and require phosphorus, but applications should not be made without determining the available P(2)O(5) present. It is believed that when nitrogen and potassium are limited and phosphorus fixation is at a minimum, phosphate recommendations for cotton and sorghum may be made on the following basis: Soils containing less than 6 ppm available P(2)O(5) require liberal applications, those containing from 6 to 15 ppm require light applications, but those containing more than 15 ppm require very little or no phosphorus.

It is shown that the failure of wool to reach equilibrium with alkaline solutions under the conditions of titration experiments is due to the reaction of base with the disulfide groups of the cystine. The results indicate that the extent of this reaction can be determined. The data also afford confirmation of the earlier observation that the alkali degradation of the cystine in wool involves the loss of only one sulfur atom from each cystine residue. The apparent base-combining capacity increases with increasing duration of contact of wool with alkali and with increasing temperature, but the intrinsic base-combining capacity, obtained by making corrections for the dissolved, protein and for the base bound by the sulfhydryl groups, becomes constant after approximately two hours. The most consistent data are obtained at a low temperature where, it appears, secondary reactions are greatly inhibited. Determination of the amount of base absorbed from solutions of various concentrations indicates that a limiting amount of about 0.7 millimole per gram of wool is reached above concentrations of about 0.2 N sodium hydroxicte. Because of discrepancies in the data obtained at concentrations greater than 0.3 N, it is suggested that this value be considered for the present as tentative.

Summary and ConclusionsA comparison of methods for determining soil reaction and lime requirements of soils was made, using 150 soils that were representative of the three soil provinces of Virginia. The rapid tests, given in order of their accuracy, which was determined by comparison with the hydrogen electrode method, are: LaMotte-Hester, Hellige, Modified Indiana, LaMotte-Morgan, Missouri Potassium Thiocyanate, and Soiltex. The glass electrode method proved to be more accurate than the quinhydrone electrode method. Using accuracy, cost, and general adaptability as criteria, the results of this investigation indicate that the LaMotte-Hester method is best adapted for use under Virginia conditions, where the facilities necessary for its operation are available. The Modified Indiana method was found to be the most accurate and cheapest method adapted to actual field use. Of the laboratory methods evaluated, the results indicate that the glass electrode method is preferable to the quinhydrone electrode method on the piedmont and limestone valley and uplands soils of Virginia, while there appears to be little choice between the two methods on soils of the coastal plains province of Virginia.