Progress of Invention. 239 



power, by replacing 1 the nitric acid with an aqueous solution of 

 perchloride of iron. He found that substituting a solution of chlo- 

 ride of sodium for sulphuric acid, left the battery still very effective, 

 and that even if the zinc is surrounded with pure water the battery 



is well suited for telegraphy. Antozone.- — -The existence of this 



substance has been the subject of serious doubt. Schonbein has, 

 however, obtained it, by means of a powerful galvanic battery. He 

 found its specific gravity less than that of hydrogen ; it is, therefore, 

 the lightest substance known. It is liquified by a pressure of 150 

 atmospheres. Mixed with ozone, it is exploded by the non-lumi- 

 nous rays of the spectrum, and by positive, but not by negative 

 electricity. If this latter fact shall have been established by fur- 

 ther experiments, it will afford a seemingly unanswerable proof of 

 the existence of two electricities. Neio Mode of Softening Pho- 

 tographs. — M. Mathey, for this purpose, interposes a lace veil 

 between the sitter and the camera — the nearer the latter, the more 

 useful it is. It produces the effect of a drawing in chalks ; and 

 softens down prominent characteristics in the. model which would 

 impart harshness to the picture. New Mode of Silvering Mir- 

 rors.- — Two-thirds of an ounce of platinum are dissolved, with the 

 aid of heat, in two ounces and a-half of hydrochloric acid and one 

 ounce and a-sixteenth of nitric acid. The solution is next evapo- 

 rated, and the residue is pulverized and dissolved in alcohol. The 

 alcoholic solution is applied to the glass, which is then heated to 

 a cherry red, and afterwards cautiously cooled. An excellent, a 



very durable, and a cheap reflecting surface is thus obtained. 



Application of the Magnesium Light to Medicine. — The laryngoscope 

 is an instrument consisting of two mirrors, and is used for in- 

 spection of the throat, etc. It has been rendered much more effec- 

 tive by employing for its illumination the light of burning mag- 

 nesium. The rays from the ignited metal are thrown on the mirror 

 situated at the end of the throat, and projected downwards, so as 

 brilliantly to illuminate the larynx and trachea, and form their 

 image in the other mirror. The minute image thus obtained is 

 greatly magnified, by means of a double convex lens, which is held 

 in front of the patient's mouth ; and the smallest symptoms of 

 disease in the respiratory passages are rendered distinctly visible. 

 Improvement of the Jaquard Loom. — The necessity for cumber- 

 some and expensive cards has always been found a source of great 

 inconvenience with this loom ; but they have been, at length, 

 rendered unnecessary by M. Acklin, a French engineer, who has 

 substituted for them punched paper, which saves about one-third of 

 the cost, renders lacing — a tedious process — unnecessary, and econo- 

 mizes both labour and time, while it enables the work to be exe- 

 cuted more perfectly. The invention is applicable to looms already 

 in use, 



