MISCELLANY. 



509 



200 gallons. In the bottom portion of this 

 structure are pumps for the purpose of 

 forcing a liquid, chemically prepared, into 

 the vessels above. The principal ingredient, 

 besides water, is sulphate of copper. From 

 these vessels two systems of tubing are car- 

 ried downward to the ground, and con- 

 tinued along the surface forward to a dis- 

 tance of a couple of hundred yards, in a 

 direction at right angles to the front of the 

 rectangular structure already mentioned. 

 Raised at slight elevation from the ground, 

 and placed at right angles to these tubes, he 

 the trees to be operated upon, with their 

 thicker ends inward ; at intervals of 12 or 

 15 inches, in this horizontal tubing, is placed 

 a series of taps, each connected by a short 

 India-rubber tube to the end of a tree, to 

 which it is secured by means of cramps and 

 screws, and rendered water-tight by a sort 

 of nozzle. By means of cocks at the upper 

 end of the horizontal piping, the solution 

 in the vats is permitted to descend. The 

 pressure exerted from above forces it into 

 the pipes through the India-rubber tubing 

 and into the trees, traversing them in the 

 direction of their fibre. In a short time, the 

 sap and a portion of the chemical solution 

 are seen to ooze slowly from the smaller end 

 of the tree, when it falls into a sort of 

 wooden gutter, inclined at such an angle as 

 causes it to run back to a cistern near to 

 where it had been originally prepared. 

 After undergoing some filtration here, it is 

 placed along with the yet unused liquid, and 

 again performs the circuit of the vats above 

 and trees below. The time necessary for the 

 complete saturation of the trees varies from 

 ten days to three weeks, according to their 

 quality and age. In this way an application 

 of the principles of hydrodynamics, com- 

 bined with what is little more than a me- 

 chanical chemical knowledge, enables the 

 manufacturer to provide poles for tele- 

 graphic purposes which will resist the action 

 of the atmosphere for at least five times as 

 long as the telegraph-poles formerly in use. 



Propagation of Disease. At a late meet- 

 ing of the Manchester Philosophical Society, 

 the president, in some remarks on the prop- 

 agation of disease, pointed out how this 

 might occur through house - drains that 

 emptied into sewers. The sewer, acting as 



a reservoir, receives the diseased emanations 

 from one house, only to send them back 

 through improperly - trapped drains into 

 other houses. Proof of this being a pos- 

 sible mode of spreading disease was fur- 

 nished by a case, where, in one of the streets 

 of a town suffering from an epidemic of 

 small-pox, several houses on one side of the 

 street were visited by the disease, while on 

 the other side every house escaped. This 

 circumstance was all the more remarkable 

 from the fact that, on the side affected, the 

 yards and spaces about the houses were 

 clean and dry, while on the other side " the 

 privies and slops overflowed the yards and 

 lanes, and the stench was almost unbear- 

 able." On the clean side, the houses were 

 connected with the sewer, sewage-gas was 

 within them, and so was the epidemic. On 

 the dirty side, none of the houses communi- 

 cated with the sewer, and all were free from 

 the disease. " Thus untrapped or badly- 

 trapped drains, terminating in sewers, may 

 be worse than no drains at all." 



Detection of AInm in Bread. Anybody 

 who wishes to test his bread or flour, for 

 the presence of alum, may do so by the 

 following process, which we find described 

 and vouched for by Mr. John Horsley in a 

 recent number of the Cliemical News, First, 

 make a tincture of logwood, by digesting, for 

 eight hours, two drams of freshly-cut log- 

 wood-chips, in five ounces of methylated 

 spirit, in a wide-mouthed phial, and filter. 

 Second, make a saturated solution of car- 

 bonate of ammonia in distilled water. A 

 teaspoonful of each solution mixed with a 

 wineglassful of water, in a white-ware ves- 

 sel, forms a pink-colored liquid. Bread con- 

 taining alum, immersed in this liquid for 

 five minutes or so, and then placed upon a 

 plate to drain, will in an hour or two become 

 blue on drying, but, if no alum is present, 

 the pink color fades away. If, on drying, a 

 greenish tinge appears, that is an indica- 

 tion of copper, as carbonate of ammonia 

 produces that color, but never a blue. 



A Singing Marmot. Dr. Lockwood's 

 theory of the latent singing capacity of the 

 Rodents has received an interesting item of 

 confirmation from an article in the June 

 number of the American Naturalist, by Dr. 



