trate of ammonia (ammonio-tartrate of iron) by acetate of lead, 

 and decomposing the precipitate by dilute sulphuric acid. 



' P. S. When lead is used in the preparation of Amphitype paper, 

 the parts on which the light has acted are found to be in a very high 

 degree rendered water proof. 



ANTHOTYPE. 



The influence of light upon the growth and germination of 

 plants is very curious and interesting. The facts connected with 

 this subject have been investigated by Mr. Chevrieul, Mr. Hunt, 

 and Sir John Herschel. To the latter gentleman we are indebted 

 for the enquiries which have led to the publication of the Antho- 

 type process. He found that the expressed juices, and alcoholic 

 or watery infusions of certain flowers, more particularly the papa- 

 ver rhoeas, the coschoous taponica, the violet rose, ten weeks' 

 stock, etc. etc. when spread on paper, were very sensitive to light. 

 To procure this colouring matter, the petals of fresh and well- 

 selected flowers are bruised to a pulp in a marble mortar, either 

 alone or with the addition of a small quantity of alcohol, the 

 juice is expressed by squeezing the pulp through a piece of fine 

 linen. The paper is prepared in the following manner: "The 

 paper should be moistened on the back by sponging and blotting 

 off. It should then be penned on a board, the moist side down- 

 wards, so that two of its edges (suppose the right hand and lower 

 one) shall project a little beyond those of the board. The board 

 being then inclined twenty or thirty degrees to the horizon, the 

 alcoholic tincture (mixed with a very little water, if the petals 

 themselves be not very juicy) is to be applied with a brush, in 

 strokes from left to right, taking care not to go over the edges 

 which rest on the board, but to pass clearly over those that project; 

 and observing also to carry the tint from below upwards by quick 

 sweeping strokes, leaving no dry spaces between them, but keeping 

 up a continuity of wet spaces. When all is wet, cross them by 

 another set of strokes from above downwards, so managing the 

 brush as to leave no floating liquid on the paper. It must then 

 be dried as quickly as possible over a stove, or in a current of 

 warm air, avoiding however such heat as may injure the tint." If 



