X 



discovered at Malta. It is not possible to suppress a feeling of regret 

 that this grand instrument no longer exists. 



Mr. Lassell was very successful in the great brilliancy and perma- 

 nence of polish of his mirrors. Within the last few years the writer 

 has been shown specula by Mr. Lassell, which had been polished for more 

 than twenty years, and which appeared as bright as if but just removed 

 from the polishing machine. His earlier metal differed from that 

 employed by Lord Rosse, in that it contained a small quantity of 

 arsenic in addition to copper and tin. In the case of his four-foot 

 mirrors, the arsenic was omitted. He seems to have considered that 

 the perfection of the metal depended upon the accurate relative pro- 

 portion of the copper to the tin, and that, in consequence of the 

 uncertainty of the state of purity of the metals, this proportion would 

 be obtained with the necessary accuracy only by a series of testings, 

 while the metal was in the pot. 



After his return from Malta, Mr. Lassell purchased a residence near 

 Maidenhead, and erected there in an observatory, his equatorial tele- 

 scope of two-foot aperture. Mr. Lassell's experience in re-polishing his 

 four-foot mirror, suggested to him some alterations in his polishing 

 machine. After his return, he was able to carry out experiments in 

 connexion with the suggested alterations in a workshop erected at 

 Maidenhead, and succeeded in constructing an improved form of 

 polishing machine, which is described in the " Philosophical Transac- 

 tions" for 1874. The numerous papers by Mr. Lassell, to be found in 

 the " Monthly Notices," and the " Memoirs " of the Royal Astronomical 

 Society, bear abundant record to his industry and skill, and make us 

 feel that in Mr. Lassell's death we have to deplore the loss of one who 

 contributed largely to the advancement of the science of his age. 



Mr. Lassell was elected a Fellow of the Royal Astronomical Society 

 in 1839, he received the Gold Medal of that Society in 1849, and in 

 1870 was elected its President, which office he held for two years. 

 He became a Fellow of the Royal Society in 1849, and received one of 

 the Royal Medals in 1858. Among other honours conferred upon 

 him, may be mentioned an honorary degree from the University of 

 Cambridge, and the honorary Fellowship of the Royal Society of 

 Edinburgh, and of that of Upsala. 



Dr. William Shaepey was born at Arbroath, in Forfarshire, Scot- 

 land, on the 1st of April, 1802. His father was an Englishman and 

 belonged to Folkestone, in Kent, till the year 1794, when he migrated 

 to Arbroath, and there married Mary Balfour, a native of that place ; 

 but, he dying shortly before the birth of his son William, Mrs. Sharpey 

 was afterwards married to Dr. William Arrott, a medical practitioner 

 of Arbroath, in whose family the subject of this notice was brought 

 up. 



