263 



Mr. George Smith presented to the Academy an ori- 

 ginal portrait of General Vallancey, by Chinnery. 



The thanks of the Academy were voted to Mr. Smith 

 for his valuable donation. 



Mr. William Bald, civil engineer, read a paper, contain- 

 an account of his models of the Island of Achil, Clare Island, 

 and the south western district of Mayo, which comprises 

 the greater part of the barony of Murrisk, and a portion of 

 the barony of Burrishoole. 



After an introduction, in which the author calls atten- 

 tion to modelling, as the best mode of representing the rise 

 and fall of ground, and makes some remarks on the unde- 

 served neglect which the subject has hitherto met with in 

 this country, he proceeds to state, that his model of Clare 

 Island was made on a scale of eight inches to the Irish mile ; 

 and that the models of Achil Island, and Murrisk Barony, 

 were on scales of four inches to the English mile. The ver- 

 tical scales were the same as the horizontal. The model 

 of the barony of Murrisk is at present deposited in the 

 house of the Royal Dublin Society. The original model 

 of Clare Island is in the possession of the Royal Society 

 of Edinburgh ; and the model of Achil has been deposit- 

 ed in the Museum of the College of Edinburgh. The 

 model of Murrisk represents the area of a country con- 

 taining nearly two hundred square miles ; that of Achil repre- 

 sents a country containing about fifty-eight square miles ; 

 and Clare Island is about four English miles long, by two 

 and a quarter in its greatest breadth. These models were 

 constructed with a composition of putty, white lead, and 

 cork. The paper gives an account in detail of the mode of 

 their construction. 



In ascertaining the levels of the country, Mr. Bald re- 

 commends that lines of equal level be adopted, and also 



