Dr. Anderson on the Nalro-Boro-Calciie. 293 



easily take account of it. When the thickness of it increases or its con- 

 ductibilities decrease, the temperature of the exterior surface increases. 

 This is a fact well known, for in cast iron boilers the exterior surface 

 often becomes red hot ; and as to malleable iron boilers, the alteration 

 which they experience from the action of the heat increases with their 

 thickness, but as the quantity of heat which they transmit increases 

 with the temperature of the exterior surface, we conceive the influence of 

 the nature and thickness of the metal to be very feeble." 



Fehruary 16, 1853.— Dr. George Walker Arnott in the Chair. 



Mr, Malcolm M'Niel Walker was elected a member. 



Mr. Donaldson and Mr. Taylor were admitted as members. 



The following motion was proposed by Mr. W. J. Macquorn Rankine, 

 and seconded by Dr. Walter Blackie : — 



" That the office-bearers of the Society be requested to prepare and 

 sign a memorial to the Lords of Her Majesty's Treasury, in support of 

 the application of the Town Council of Glasgow, recommending that the 

 Ordnance Survey of the Municipality of Glasgow be made on a scale of 

 ten feet to one mile, and be conducted with vigour by means of an ade- 

 quate supply of funds." 



The motion was supported by Mr. D. M'Kain, Mr. Andrew Liddell, 

 and Mr. William Bi-own, and unanimously agreed to. 



The following paper was read : — 



XXXIX. — On the Natro-Boro-Caldte, or ' Tiza^ ofjquique. 

 By Thomas Anderson, M.D. 



The object of the present communication is to bring under the notice 

 of the Society a mineral of considerable scientific and practical interest, 

 the former dependent on the remarkable conditions under which it is 

 found, the latter on the possibility of its becoming an important com- 

 mercial article, as a source from which boracic acid and borax may be 

 obtained. The specimen which I have examined and analyzed is part of 

 a considerable quantity which has been imported into this country with 

 the view of ascertaining its mercantile value. 



The mineral was originally discovered some years since, and was 

 described and analyzed under the name of Hydro-Boro-Calcite, by an 

 American chemist, Hayes, who found it to consist of boracic acid, lime, 

 and water. Since then it has been analyzed by Ulex, who detected in it 

 a quantity of soda which Hayes had overlooked, and altered its name 

 to Natro-Boro-Calcite. With the exception of these observers no 

 person has examined it, and it appears to have excited comparatively 

 little attention, for the now edition of " Phillips's Mineralogy," by Brooke 

 and Miller, published last year, contains only a very cursory notice of it. 



