74 Scientific Intelligence, [July, 



on the positive pole, and then to undergo fusion by intense heat. In 

 about three seconds, a decisive result is obtained. 



Charcoal, which has been thus fused, is found to have acquired a 

 great increase of specific gravity. It sinks readily in strong sulphuric 

 acid, though common charcoal floats readily in water with at least 

 half its volume out. It is rendered also very difficult of combustion, 

 but may be burned away, leaving no residuum if heated by a powerful 

 lens in a vessel over mercury filled with oxygen gas. The gas produced 

 was ascertained to be pure carbonic acid. Strong sulphuric acid may 

 be boiled without effect on charcoal which has been fused. Even the 

 strongest nitric acid in the cold docs not act upon it, and at a boiling 

 temperature, the action is very slight, and ceases the moment the heat 

 is withdrawn. — (American Journal.) 



XIV. Alteration of thejreezing Point of Thermometers hy being long 



kept. 



It is asserted (Annales de Chimie et de Physique, Nov. 1822, 

 p. 330), that a thermometer on which the freezing point has been 

 exactly marked, becomes incorrect in process of time, at the end of a 

 year for example, and indicates, when plunged into melting ice, a 

 temperature a little above freezing, as if the bulb had become smaller. 

 This fact, originally observed by Bellani, of Monza, in the Milanese, 

 was confirmed by Pictet's experiments in six different thermometers. 

 In one of these, made 40 years ago, the freezing point had risen to 

 4- 0*1 centigrade. M. Flaugergues, the astronomer, after satisfy ini^j 

 himself of the fact, has endeavoured to assign a reason for it in the dimi- 

 nishing elasticity of the glass of the thermometric ball, which, like all 

 other springs, loses its force by being kept long in a state of tension." 



A correspondent of the Editor of this journal has been induced, by 

 the foregoing notice, to examine several thermometers which he has had 

 for many years; but has not been able to discover the deviation above 

 remarked. Two of these, made by Crichton, of Glasgow, having very 

 small cylindroidal bulbs, have been in his possession nearly twenty years. 

 In these, the freezing point is marked by a file on the stem, and when 

 plunged into thawing snow, not the smallest change is observable in the 

 height at which the mercury now stands. In one or two others, out of 

 ten which were examined, there did appear a little deviation from the 

 freezing point marked upon them; but they had not been constructed 

 by makers of any eminence, and had probably been inaccurate from 

 the first. The change, therefore, though scarcely to be questioned on 

 such testimony, appears not to be universal. 



XV. Excremejitqfthc Bon. 



Prof. Psaff found that the fresh solid excrement of tlie boa is insolu- 

 ble in cold water, but dissolved by about 800 times its weight of boil- 

 ing water. The greater part of what is dissolved is deposited as the 

 water cools, and this deposit is partly pulverulent, and partly on fine 

 shining scales, circumstances which characterise uric acid. 



With nitric acid, the general phenomena exhibited by uric acid were 

 also produced, but the Professor observed, that when evaporated with 

 nitric acid to a certain point, and before purpuric acid is formed, the 

 solution deposits a considerable quantity of crystallized nitrate of 

 ammonia ; after the first portion of crystals were separated by evaporat- 



