British Association for the Advancement of Science. 303 



but one species of the general effects which usually occur in chem- 

 ical actions, all of which are modifications of universal gravity 

 arising from circumstances. 



Mr. William Herapath gave a paper on a neiD process for tan- 

 gling. He assumed that the great cause of obstruction to rapid 

 tanning, is, that the weakened ooze is retained by the capillary 

 attraction of the fibres and blood-vessels so long, that when it 

 shall have passed out by exosmosis, it will have produced the 

 same effect upon the soluble gelatin as is produced by maceration. 

 Hydraulic pressure was too expensive, and he accordingly thought 

 of employing pressure by the roller. 



On the application of gas obtained hy Water to the Tnanufac- 

 ture of Iron .^ by Mr. J. S. Dawes. The mode is as follows. Jets 

 of steam are made to pass through red hot cast-iron pipes, filled 

 with small coke or charcoal ; decomposition immediately takes 

 place ; the base of the carbon of the coke combines with the ox- 

 ygen base of the steam, forming, at first, carbonic acid, but by 

 passing this over a further portion of red hot carbon, it is con- 

 verted into carbonic oxide, sensible heat at the same time becom- 

 ing latent on combining with the hydrogen base, producing hy- 

 drogen gas, which, together with the oxide before mentioned, is 

 applied to the furnace by means of a jet inserted within the blast- 

 pipe tuyere, the pressure of the gas, of course, being equal to that 

 upon the blast. 



A description, by Prof. Miller, was next read, of an improve- 

 ment in the cojistruction of the Reflective Goniometer., hy lohicli 

 it is rendered more portable. 



Dr. T, Thomson gave an account of Galactin, a substance 

 which constitutes the principal ingredient in the sap of the Cow 

 tree, or Galactodendron utile of South America. The sap, on 

 standing, throws up a white matter, soluble in boiling alcohol, 

 but deposited as that liquid cools. When well washed and dried 

 in vacuo, over sulphuric acid, it constitutes galactin. It is yel- 

 low, translucent, and brittle, has a resinous aspect and is tasteless. 

 It is insoluble in water, but soluble in alcohol and ether. Gravity, 

 0.969. It dissolves readily in oil of turpentine and olive oil. It 

 is composed of 6 atoms carbon, 4.54-6 atoms hydrogen, .75 -fl 

 atom oxygen, 1, = 6.25, being isomeric with Brazil wax. 



The secretary. Prof. Miller, read a paper on Lieut. Morrison's 

 instrument for measuring the electricity of the atmosphere, and 



