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OBITUAEY. 



H. J. Grayson, 



Mr. H. J. Grayson, whose name is familiar to microscopists 

 through his micrometers and test rulings, died on March 21, 1918,. 

 at the age of 61 years, Mr. Grayson, who was a native of York- 

 shire, visited Australia and New Zealand as a young man, and 

 after a temporary return to England settled in Victoria, where for 

 some years he followed his occupation of horticulturist. He was 

 early attracted to microscopical studies, and made many collections 

 of diatoms from various localities in Australia and New Zealand ; 

 he was also skilled in the preparation of botanical sections, and 

 especially of petrol ogical sections, of which he supplied many to 

 the Melbourne University. He first joined that institution as an 

 assistant in the Physiological Department, but was soon transferred 

 to the Geological Department. The highly efficient apparatus 

 used there for preparing rock -sections was designed by Mr. Grayson, 

 whose description of it in the Proceedings of the Ptoyal Society of 

 Victoria was reprinted in the Journal of this Society for 1911 

 (p. 703), accompanied by a detailed description of his method of 

 working. 



Before 1894 Grayson had devoted his attention to the subject 



of test-rulings on glass, and in that year specimens of the work 



done by him on a machine designed and constructed by himself 



were sent to the Eoyal Microscopical Society and reported upon 



by Mr. Nelson, who found his rulings to be very accurate, and not 



showing irregularities in spacing such as are often seen in liobert's 



plates. " (J.R.M.S., 1895, p. 134.) Signs of crystallization or 



sweating were, however, already perceptible, and in a letter 



written about that time Grayson explains the experiments made 



by him with the object of obviating this defect. His best results 



were gained by using shellac rings thoroughly hardened, and 



attaching the cover by the application of so much heat as only 



just sufficed for the purpose. A longer experience, however, 



satisfied him that the dry mounting plan was never absolutely 



reliable, and led to his turning his attention to other methods, 



resulting in his adoption of a process of mounting in realgar. 



Micrometers and test-plates mounted in this medium, sent to the 



Society in 1898, and examined by Mr. Nelson, were considered to 



be the finest yet produced, whether from the point of view of the 



accuracy of the rulings or the distinctness and brilliancy due to 



the mounting medium. An accompanying photo-micrograph of 



