Description of the Acorn Dibble. 39 



ments, and philosophical apparatus; to prevent the destruc- 

 tive effects of the atmosphere, and to preserve them from 

 the agency of acid? and other corrosive subslances, 1 can- 

 not but indulge a hope that these new compounds will 

 admit of some applications of this kind. I made some at- 

 tempts to plaie steel, iron, copper and brass with (he super- 

 sulphuret and super-phosphuret of platina, but obtained no 

 very saiisfactorv results ; the coatings were in some cases 

 very partial, and in others not permanent. It will be un- 

 necessary to enter more into detail, as Mr. James Stodart 

 and myself intend to resume the subject, and to make the 

 experiments in a more refined manner. 



It beems probable that the combinations of sulphur and 

 phosphorus with platina exist in nature, and M. Proust* 

 considers the black povAder remaining after the ore of 

 platina has been digested in nitro-muriaiic acid, as contain- 

 ing both sulphuret and phosphuret of platina : new re- 

 searches however are wanting in order to establish this point. 



The phosphurets of platina described in this paper differ 

 materially from the combination ootained by M. Pelletier, 

 both in the proportions of phf.sphorus thev contain, and in 

 their sensible properties. The methods hitherto employed 

 to form the class of metallic phosphurets appear to be very 

 imperfect, and can scarcely furnish in any instance correct 

 results; they are quite impracticable m some cases. Thus 

 the phosphurets of gold and mercury can only be formed 

 at comparatively low temperatures ; and the phosphuret of 

 gold is entirely decomposed by a moderate heat. Other 

 instances might be mentioned in which the existing com- 

 binations are partially destroyed at more elevated tempe- 

 ratures, as the phosphuret of nickel and the super-phos- 

 phuret of platina. The new mode 1 have adopted, that 

 of healing the metals and phosphorus in an exhausted tube 

 hermetically sealed, seems to me to be simple and accurate, 

 and in its application promises to furnish more correct re- 

 sults than have yet been obtained. 



VIII. Description of an Acorn Dibble, invented vy Mr. 

 Charles Waistell, of High Holbornf. 



Sir, In consequence of information that Government 



* /tnnales tie Chimie, tome xxxviii. p. 171. 



■|- From Trnnsactions of the Svrielt/ for the Riumtra/^email i>f /trh, Mnnufac 



tures, and Commerce, (or 1811. The Society are indebted to Mr. W.TistclI 



for thi» improvement. One of these instrunienti> i» preserved in the Society's 

 Repository. 



C4 wanted 



