Miscellanies. 185 



perceptible impression, and that (interfering only for a moment with 

 the light reflected from the road,) they do not prevent a nearly accu- 

 rate picture of it being produced. 



Vacillating objects make indistinct pictures, e. g. a person getting 

 his boot cleaned by a decrotteur gave a good picture, except that hav- 

 ing moved his head in speaking to the shoe-black, his hat was out of 

 shape, and the decrotteur's right arm and brush were represented by a 

 half-tinted blot, through which the foot of the gentleman was partially 

 visible. 



There can be no doubt that when M. Daguerre's process is known 

 to the public, it will be immediately applied to numberless useful 

 purposes, as by means of it, accurate views of architecture, ma- 

 chinery, &c., may be taken, which being transferred to copper or to 

 stone, may be disseminated at a cheap rate ; and useful books on ma- 

 ny subjects may be got up with copious illustrations, which are now 

 too costly to be attainable: even the fine arts will gain, for the 

 eyes accustomed to the accuracy of Daguerrotype pictures, will no 

 longer be satisfied with bad drawing, however splendidly it may be 

 colored. In one department, it will give valuable facility. Anatom- 

 ical and surgical drawings, so difficult to make with the fidelity which 

 it is desirable they should possess, will then be easily produced by a 

 little skill and practice in the disposition of the subjects and of the 

 lights. 



It is a curious circumstance that, at the same time that M. Da- 

 guerre has made this beautiful and useful discovery in the art of deline- 

 ation, another Parisian artist* has discovered a process by which he 

 makes solid casts in plaster of small animals or other objects, without 

 seams or repairs, and without destroying the model, (Moulage d'une 

 seule piece, sans couture ni reparage, et avec conservation parfaite du 

 modele). lam in possession of several specimens of his work, among 

 which are casts of the hand of an infant of six months, so delicately 

 executed, that the skin shows evident marks of being affected by some 

 slight eruptive disease. I am, dear Sir, very faithfully yours, 



John Robison. 

 James Tod, Esq., Secretary to the Society of Arts. 



Edinburgh, 1st June, 1839. 



2. Correction of an error — Cinnabar not found in 3Iic7iigan. — In Vol. 

 I, at page 33, of this Journal, it is stated in a letter to Dr. J. L. Comstock 

 by B. F. Stickney, that " a black and garnet colored sand is found on the 

 shores of Lake Erie and Michigan which is a sulphuret of mercury and 

 yields about 60 per cent, of that metal." No confirmation of this too 



* Hippolyte Vincent, Mouleur, Rue Neuve St. Francois No. 14 (au Marai). 

 Vol. XXXVII, No. 1.— July, 1839, bis. 24 



