4 DEPAETMENT OP AGRICULTURE BULS. 501-525. 



Department Bulletin No. 507. — Studies on the Digestibility op Some 



Animal Fats: Page. 



Introduction 1 



Experimental methods 2 



Digestion expeiiments — chicken fat, goose fat, brisket fat, cream, and fat 



in egg yolk and in fish 4 



Summary 18 



Department Bulletin No. 508. — Yields from the Destructive Distilla- 

 tion OF Certain Hardwoods: 



Purpose of experiments 1 



Plan of investigation 2 



^lethod of recording data 2 



Yields on per cent weight basis 2 



Yields per cord, alcohol, and acetate 3 



Pyroligneous acid, tar, and charcoal 7 



Commercial distillation 8 



Department Bulletin No. 509. — The Theory op Drying and its Appli- 

 cation to the New Humidity-regulated and Recirculating Dry Kiln: 



Introduction 1 



Elementary principles of drying 2 



Elementary principles of hygrometry 5 



Types of kilns 7 



Drying by superheated steam 8 



Importance of proper piling of lumber 9 



Theory and description of the Forest Service kiln 10 



Theoretical discussion of evaporation 13 



Theoretical analysis of heat quantities-. 18 



Department Bulletin No, 510. — Timber Storage Conditions in the 

 Eastern and Southern States with Reference to Decay Problems: 



Introduction 1 



Cause of decay in timber 2 



Handling timber at sawmills 7 



Location of mills and its relation to decay 8 



Quali cy of stock with reference to decay 9 



Condition of storage sheds at mills 10 



Condition of storage yards at mills 11 



Handling timber at retail yards 27 



Fungi which rot stored lumber 30 



Wood preservatives in the lumber yard 38 



Branding structm-al timber 40 



Conclusions 41 



Department Bulletin No. 511.— Farm Practice in the Cultivation op 

 Cotton: 



Introduction 1 



General statements 3 



Subsoiling 4 



Drainage 5 



Tillage before plowing 6 



Plowin'g 6 



Preparation after plowing 9 



Planting 10 



. Normal averages of farm conditions 12 



The relation of crop rotations to crop yields 14 



The relation of tillage and price of land to crop yields 15 



Groilps of cotton-growing areas 16 



General farm practices and conditions 17 



Summa,ry 61 



Department Bulletin No. 512. — Prevention of the Erosion op Farm 

 Lands by Terracing: 



Introduction 1 



Forms of erosion 2 



Methods of preventing erosion 3 



Terracing 5 



Reclamation of gullied lands 38 



Summary 38 



