132 The Naturalist of Cumbrae. 



pocket lens of a quarter of an inch focus, with an 

 adjusting screw for the plate that held the plant. This 

 simple form of microscope, made by an Edinburgh 

 optician named Bryson, he found exceedingly useful 

 for field work, nor has he met with anything since 

 that could answer the particular purpose better. But 

 for closer examination of the algae at home a com- 

 pound microscope was required. His friend Mr. 

 Hennedy had one by Nachet, the well-known French 

 maker, which he had procured through Dr. Arnott, 

 Professor of Botany in the University of Glasgow. 

 Dr. Arnott kindly offered to order one for Mr. Robert- 

 son, his intervention securing for him, as was expected, 

 an excellent instrument, although it may very well be 

 supposed that the instrument would have been just 

 as good if ordered in his own name. 



The study of sea-weeds eventually brought him into 

 an agreeable correspondence both with Dr. Arnott and 

 with Dr. Harvey, the distinguished algologist, who was 

 Professor of Botany in the Royal Dublin Society. 



It so happened that, in the year 1857, a woman 

 picked up on a rubbish heap a packet containing a 

 collection of sea-weeds. This she carried to a Dr. 

 Lyndsay. This gentleman, knowing that Mr. Robert- 

 son was interested in marine plants, sent them on to 

 him. He saw at once that they did not belong to this 

 country, and were likely to be of value to the intended 

 recipient, but after applying to several of his friends 

 interested in such specimens, he could find no trace of 

 the owner. There was, however, among them, by some 

 accident, a letter and an envelope addressed to Dr. 

 Harvey, Dublin. To him therefore he wrote, and re- 



