When a boy young Voelcker spent all his leisure hours in collecting plants, minerals, insects, and other objects of natural history; as his taste for natural science was greatly promoted by the scientific lectures given in the Botanical Garden at Frankfort. At the age of eighteen years he had gathered an extensive herbarium and was familiar with the flora of South-Germany; while so much was be devoted to the study of Botany as at that time to entertain serious thoughts of taking up Botany as a profession. During his sojourn at the University of Gottengen, he attended the lectures on Mathematics, Natural Philosophy, Mineralogy, Geology, Botany, Vegetable and Animal Physiology, and Chemistry, delivered by the Academical Professors; but while he took a special interest in the pursuit of Chemical studies, directed by Professor Wobler, in whose laboratory he worked for several years; and where when a student, he published several original chemical investigations of a purely scientific character.

On the recommendation of Professor Wobler, M. Voelcker was appointed principal assistant to Professor Mulder, of the University of Utrecht in Holland, the author of the Proteintheory and a distinguished physiological chemist, with whom to this day he remains attached on terms of intimate friendship. Whilst in Holland Dr. Voelcker made the acquaintance of the late Professor Johnston, of Edinburgh, the author of Lectures on Agricultural Chemistry and Geology, and the Elements and Catechism of Agricultural Chemistry; and on the appointment by the Dutch Government of Professor Johnston's assistant, Dr. Fromburg, to a distinguished position, Dr. Voelcker was invited to superintend the Laboratory of the Agricultural Chemistry Asso

incorporated with the Highland and Agricultural Society of Scotland. Accepting this invitation he went to Edinburgh in 1849, and for two years remained a co-labourer with the late Professor Johnston, with whom he spent a short time at Durham on the amalgamation of the Agricultural Chemistry Association with the Highland Society. Eventually, however, he returned to Edinburgh, where he had many scientific friends, as amongst others the late Professor Gregory, Dr. George Wilson, and Professor Balfour, occupying, as usual, himself with scientific pursuits.

In 1851 Dr. Voelcker was appointed Professor of Chemistry in the Royal Agricultural College at Cirencester, succeeding there Dr. Blythe and his predecessor, Professor Way. After four years' residence at Cirencester he was appointed Consulting Chemist to the Bath and West of England Agricultural Society, and in 1857, on the resignation of Professor Way, Consulting Chemist to the Royal Agricultural Society of England. For a period of five years he held both appointments; but finding the work in connection with the Royal Agricultural Society increasing from year to year, and too much interfering with the delivery of lectures and his other duties in Cirencester College, he resigned the Professorship and removed to London in 1862, retaining his appointment as Consulting Chemist to the Royal Agricultural Society up to the present time.

Dr. Voelcker is a member of the Committee of the Farmers' Club, in whose proceedings he takes an active interest, and where he has frequently delivered the opening address at the discussion meetings. He has indeed given lectures throughout the length and breadth of England, and published numerous original investigations, as well as four Lectures on Agricultural Chemistry, a Treatise on the Chemistry of Food, &c.

Dr. Voelcker is the author of all the chemical articles in Morton's Cyclopædia of Agriculture; and editor of the last edition of Johnston's Catechism of Agricultural Chemistry and Geology; while his more important original experi

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are:

1. On Farm-yard Manure, and the chemical changes it undergoes in keeping.

2. On Liquid-manure, and the changes it undergoes in passing through soils of known composition.

3. On the Causes of Efficacy of Burnt Clay, and on Paring and Burning.

4. On the Chemical Properties of Soils. 5. Papers on Experiments Relating to the Absorption and Retention of Ammonia and its Salts by Soils, the Absorption of Potash and its Salts, of Phosphoric-acid, &c.

6. On the Functions of Soda-salts in Agriculture. 7. Dairy Investigations. (The Chemistry of Milk and Cheese.)

8. On Phosphatic Materials Used in Agriculture. 9. On the Nutritive Properties of different kinds of Straw.

10. On Peruvian Guano, and the Means of Rendering it more Efficacious.

11. On Disinfectants.

12. On Hay-making.

13. Researches on the Growth of Clover. 14. Numerous Field Experiments.

The following is a chronological list of Dr. Voelcker's papers:→→

1. On Anthracite of the Calton Hill, Edinburgh. 2. On the Watery Secretion of the leaves and stems of the Ice Plant. (Mesembryanthemum crystallinum.)

3. On the Secretion of Nepenthes destillatoria. 4. On the Composition of the Ash of Ameria maritima, grown in different Localities; with Remarks on the Geographical Distribution of that Plant, and on the presence of Fluorine in Plants.

5. On the Relative and Fattening Value of Linseed and Rape-cake.

6. On the Effects of Burnt Clay as a Manure. 7. On the Comparative Value of White Scottish and Black English Oats, and on the Composition of Rice-meal.

8. On the Composition of Green Rye and Rape. 9. On the Composition of the Parsnip, and White Belgian Carrot.

10. On the Comparative Value of different Artificial Manures for raising a crop of Swedes. 11. On the Agricultural and Commercial Value of some Artificial Manures, and on their Adulteration.

12. On the Chemistry of Food. 13. Four Lectures on Farm-yard Manure, Artificial Manures, Barren and Fertile Soils, Oilcakes, &c.

14. On the Composition of Farm-yard Manure, and the Changes which it undergoes on Keeping, under different circumstances. 15. On Farm-yard Manure, the drainings of Dungheaps, and the absorbing Properties of Soils. 16. On the Use of Lime, Marl, and Shell-sand in Agriculture.

17. On Paring and Burning.

18. Experiments upon Swedes, with Remarks on the Manures employed.

19. On Liquid-manure,

21. On Anbury, and the Analysis of Diseased Turnips.

22. On the Composition of a Mangold-wurzel kept for two years.

23. On the Composition and Nutritive Value of Cotton-cake.

24.

On the Composition and Nutritive Properties of Mangold-pulp (the refuse of Beet-root Distilleries).

25. On the Composition of two varieties of KohlRabi, and of Cattle-cabbage.

26. Experiments with different Top-dressings upon Wheat. 27. On the Composition of Sorghum saccharatum (Holcus saccharatus), or North China Sugar-cane.

28. On the Chemical Properties of Soils. 29. On the Composition of Purton Saline Water. 30. On the Composition of the Yellow Lupine, and a Soil suitable to its culture.

31. The Composition and Value of Norwegian Apatite, Spanish Phosphorite, Coprolites, and other Phosphatic Materials. 32. Reports on the Constituents of Manures. 33. Experiments on Swedes.

34. On the Composition of Cheese, and on Practical Mistakes in Cheese-making.

35. On the Scouring Lands of Central Somerset. 36. On the Composition and Nutritive Value of Straw.

37. Experiments with different Top-dressings upon Wheat.

38. Lecture on Farm-sewage.

39. On the Commercial Value of Artificial Manures. 40. On Poisonous Cheese. 41. Cheese Experiments.

42. On the Absorption of Phosphate of Lime, and Phosphatic Manures for Root-crops. 43. Experiments with different Top-dressings upon Wheat.

50. Absorption of Potash by Soils of known Composition.

51. On some Causes of Unproductiveness of Soils. 52. On the Composition and Nutritive Value of Palm-nut Kernel-ineal and Cake.

53. Annual Report, 1866. 54. Report on the Improvements of Grass-land at Mr. Ruck's Farm, Braydon, Wilts. 55. On the Functions of Soda-salts in Agriculture. 56. Field Experiments on Clover-seeds. 57. On Disinfectants.

58. On the Composition of Orange Globe Mangolds, bulbs or lops.

59. The Changes which take place in the Field and in the Stack in Hay-making.

60. Field Experiments on Crude German Potashsalts and Common Salt on Mangolds,