Don Bustamente 07i a neiv Gravimeter. 207 



One of the English pupils of Professor Del Rio presumes 

 to suggest, that it would be but an act of justice to that pro- 

 found mineralogist and eminent scholar to state, that, as far 

 back as the year 1804, he stated in a note at page SS of his 

 translation of Karsten's Mineralogical Tables, that he had 

 made the same discovery, as will be seen from the following 

 extract : — 



Los cristalitos de olivino de Zinapeguaro estan de canto so- 

 bre las eras 6 quadritos de la substancia blanca nueva que he 

 Uamado equinolita contenida an las cavidades de la obsidiana 

 de alii; siendo muy peguenos juzgue al principio por el color 

 que fueran de obsidiana ; pero al soplete no se funden, solo to- 

 man un viso negro de hierro y con borax se funden en vidrio 

 verde claro. Son de color verde a ceytuna, transparentes, 

 rayados a lo largo, y parecen tablas octagonas prolongadas con 

 todas las aristas laterales truncadas."" 



The above is from a note to Olivine, extracted from a 

 work replete with profound mineralogical knowledge ; but 

 which, from its being published in Mexico and in Spanish, is 

 but little known in Europe. 



At the same time that I submit this for your consideration, 

 I beg to inclose the description and drawing of an instrument 

 for weighing specific gravities, invented by Don Jose Maria 

 Bustamente ; the ingenuity and simplicity of which will, I 

 have no doubt, induce you to take notice of it in your excel- 

 lent Journal. It appears calculated to supersede altogether 

 the use of Nicolson's balance weight. — I have the honour to 

 be, Sir, your faithful and obedient servant, 



X. 



Mexico, SUt October 1828. 



AiiT. III. — Description and use of a new Gravimeter, By 



Don Jose Maria Bustamente. 



It is known, that, to be able to use Nicolson's Balance, a set 



of small and correct wrights is necessary, and that it requires 



to be sunk in water to a certain depth, that is, to place it in 



its index three times during the operation. Eor this it is ne- 



• It will give us great pleasure to be favoured with the continuance of 

 the correspondence of X. 



