1. The discrepancy between the results obtained by various workers concerning the inheritance of earliness or the time of ear emergence in cereals, suggests that this character needs further elucidation physiologically before genetic analysis can be properly undertaken.

2. A study of the ear emergence characteristics of varieties when grown under varying conditions indicates that the expression of this character is very much affected by the growing conditions, and the physiological basis must be understood before the various expressions of earliness and lateness are appreciated. It is therefore suggested that the genetic analysis should be conducted in conjunction with a physiological analysis and with a proper consideration and understanding of the effect of environment.

3. A series of crosses involving parental forms differing in time of ear emergence, and in some cases belonging to different physiological groups, has shown how differences in genetic behaviour can to some extent be correlated with the physiology of ear emergence of the parents.

4. In one cross involving similar types, no evidence of segregation or large genetic difference was obtained. In two crosses involving larger differences of similar types, evidence for a single major factor difference was obtained. In other crosses between different physiological types, and an unstable form, more complex genetic results including transgressive inheritance were obtained. Still other crosses superficially suggested a 3: 1 ratio in the F2, but the presence of a certain amount of transgression, and the behaviour of the F3, pointed to a more complicated relationship.

5. Two crosses involving different physiological types were studied in the F1 and the F2 when sown at different times in the spring by dividing the progenies into separate portions. It was shown that the behaviour of the F1 and the F2 of the same cross was materially affected by the sowing time.

Media from which phosphate was absent finally caused bronzing of the leaves of the resulting stunted plants of May King lettuce grown in sand culture, and red or crimson stalks. Phosphate alone produced characteristic purple (and/or bronze) and apple-green, flat, stunted rosettes with broad, non-crinkly leaves, and red stalks. Water alone caused stunted, straggly, purple plants, with relatively long, crimson stalks.

Where some phosphate was supplied in addition to the other essential elements, a plant of normal colour resulted at first. Later, purple blotches appeared on the plants receiving inadequate supplies; the intensity of this purple became greater as the amount of phosphate in the medium diminished, and it could be controlled by varying the concentration of phosphate in the medium or the frequency of application. Another deficiency symptom was the tougher leaf resulting from a lack of phosphate. A sufficiency of phosphate caused earlier maturity.

The media which contained the two greatest concentrations of phosphate were the best of those used because they gave the best growth, lettuces of the best colour without purple blotches, earlier maturity, and tenderer leaves.

The final yields of heads were statistically the same with the two heaviest phosphate treatments, and both were greater by about 40% of the lesser yields than the two statistically equal yields with the lower amounts of phosphate. All the phosphate treatments gave yields superior by about 40,000–60,000% to the non-phosphate and phosphatealone yields, but this second difference had no commercial significance. Similar results were obtained for the roots, and for the dry weights of the tops and roots.

1. An endeavour was made to obtain a blend of Tuscan wheat with a high quality line which would yield as much as Tuscan, at the same time possessing a superior baking quality. Of the eleven lines which were blended with Tuscan, nine blends returned yields corresponding to the expectation calculated from the pure varieties, and two blends yielded more than the expectation; these increases were not statistically significant.

2. Tuscan, three lines and their blends were submitted to yield analytical treatment. The yield characters of the components of blends were compared with their yield characters when grown by themselves. Whilst the yields per plot of the blends corresponded to the expectation, the yield analyses revealed that the component varieties exerted a modifying influence on each other, which was different in each of the three trials. Tuscan demonstrated its aggressiveness by depressing in every case the yield characters of the lines with which it was blended.

It is shown that the permeability of a water-saturated sand or fine powder can be calculated with considerable accuracy, if the porosity and the specific surface are known. In particular, the Kozeny theory here discussed leads to a very useful relationship between permeability and porosity. It is shown that clays do not conform to the theory in its simple form, but that it may be modified to give a satisfactory representation of the data available. The physical grounds for this modified theory are discussed in some detail, and it is shown that, while it is open to criticism, it is at least in harmony with our present knowledge of clays.

An important deduction which follows from the modified theory is that clays may have zero permeability at quite considerable porosities, e.g. at ∈ = 0·207 for a clay soil, and ∈ = 0·355 for a plastic clay.

1. The post-weaning growth of 135 litters has been analysed with a view to determining the relationship of certain arbitrary subdivisions with each other. For this purpose, the weight increases during three periods of 28 days have been denned in two ways—first, by age, the periods being 10–14, 14–18, and 18–22 weeks, and secondly, by weight, the periods beginning at 40, 80 and 120 lb. and continuing as before for 4 weeks.

2. When the periods are defined by age, the mean increase per pig per litter is affected by weaning weight, but not by litter size (Table III). The variability of the individual increases becomes greater as the pigs become older and heavier (that is, passing from one period to a later one), but less within a period as the rate of growth increases (Table IV). It was not affected by litter size.

3. The distribution of individual weights became increasingly skew with age. This is regarded as a graphical illustration of the fact that while absolute rate of growth is increasing, initially small animals must fall farther and farther behind (Graph 3).

4. The correlations between the average litter increases in different periods were calculated for litter sizes 6–11. In general, the coefficient for periods 1 and 2 was about 0·4, and for periods 2 and 3 about 0·6 (Table VI). This is interpreted to mean that, when judged by results over the whole time under observation, litters with a high correlation between the increases in weight during short periods are not properly comparable with those with a low correlation. By this method, differences in rate of growth having an important influence on carcass quality may be obscured.

The majority of methods for determining carotene involve a preliminary determination of total carotenoids, followed by a phase separation of the two pigments. This phase separation considerably limits the usefulness of such methods, and in order to dispense with it a direct extraction of carotene is necessary. For this purpose petroleum ether may be used in the presence of alcohol.

The use of hot alcoholic potash for the disintegration of leaf material and separation of chlorophyll leads to a very undesirable precipitate which hinders subsequent extraction. Two alternative methods are available, which overcome this difficulty, viz. (1) extraction with hot alcohol, followed by treatment of the extract with potash, and (2) saponification with hot aqueous potash, followed by filtration and extraction of the grass residue with alcohol. The second of these methods has been adopted, being of greater general utility and capable of producing complete cellular breakdown, which is essential for efficient extraction. Details of this extraction process have been described.

A comparison of the results obtained, with those from two other methods, has been made by a colorimetric determination of the extracted pigment. The variance and standard error have been shown to be smaller than those for the other two methods, and it has been concluded that the results obtained are reproducible with considerable accuracy.

1. A study was made of nitrogen-fixation by Azotobacter chroococcum alone in a medium containing dextrose (which it can utilize) and in mixture with a coliform organism on a medium containing no carbohydrate except starch, which Azotobacter cannot utilize unless it be hydrolysed by the coliform organism or some other agency.

2. The amount of nitrogen fixed in the mixed cultures was found to be maximal at two temperatures, and a discussion is given of the causes thought to be operative in producing the double maximum.

An investigation into the effects of lime on five acid soils in north-east Scotland has been continued during the second and third years after the application of lime and also extended to two other centres.

On four of the original soils the full effect of the lime on the surface soil has been largely maintained up to the end of the third year. The fifth, a soil of low base-exchange capacity, shows a considerable loss of lime by the end of the second year.

The lime leached from the top nine inches of soil appears to be retained to only a slight extent in the second nine inches. This was particularly noticeable on a soil of low base-exchange capacity, where, during the two years after liming, the percentage saturation of the subsurface soil showed an increase from 64 to 67%, and the surface soil a decrease from 92 to 74%.

The existence of a low liming factor (1·5), previously found to hold for a geologically basic soil, has been verified and found to apply also to a soil derived from slate.

A fundamental property of the soils with a low liming factor is the high content of inorganic and organic fine material. Secondary characteristics that distinguish these soils from the others are the relatively high values for hygroscopicity and heat of wetting.