March 28, 1890.] 



SCIENCE. 



209 



chroDometer -maker, but the navigator rating his own chronom- 

 eter is easily misled by them. 



4. There is still a point to which I wish to make a brief 

 reference ; viz. , the absolute accuracy of time-singals in 

 general ; for this question is one of great importance in rating 

 chronometers. The best data that have yet been obtained for 

 determining this question are the series of daily comparisons of 

 time-signals of the Naval Observatory at Washington, the Cam- 

 bridge (Mass.) Observatory, and the Allegheny (Penn.) 

 Observatory; this having been done for some years by Mr. 

 James Hamblett of the Gold and Stock Exchange of New York 

 City, in order to regulate the standard clock which furnishes 

 New York with accurate time. The comparisons frequently 

 show differences of two and three seconds between the observa- 

 tory standard clocks, and I believe instances are not wanting 

 in which the amounts reached even five seconds. 



Recognizing that these comparisons could not, perhaps, lay 

 claim to the greatest accuracy attainable, an elaborate plan 

 was matured some years ago by which the United States Signal 

 Service should make a daily comparison of the time-signals of 

 a dozen of our principal observatories, and thus find out with 

 certainty the accuracy attainable by a single observatory, 

 and to inquire into the desirability of the permanent organi- 

 zation of a sort of clearing-house system of time distribution, 

 by means of which a very accurate time-signal could be dis- 

 tributed over the whole country, no matter what the weather 

 might be. For various reasons this plan was not carried out, 

 but its execution is still very much to be desired. 



Taking into account the just mentioned facts, and others 

 which might be given, I think that a careful inspection of the 

 ships' chronometers and their rates should be made as fre- 

 quently as may be found possible. The exact form of this 

 inspection, which might be undertaken by the exchanges, and 

 the best method of securing the greatest accuracy in rating 

 ships' chronometers, cannot be discussed here. 



Concerning the compasses on shipboard, I will only say, as 

 has been frequently urged, that they should be examined and 

 tested at every opportunity. The possible errors of the com- 

 pass have been thoroughly studied, and those existing can be 

 accurately determined; but the subject is too technical to be 

 explained in a few words. Frank Waldo. 



CincinDati, O., March, 1890. 



Storage-Batteries. 



Many a person who has experimented with secondary batteries 

 has become convinced, as I have, that the Plante form of battery 

 was superior, especially as regards durability, to any of the vari- 

 ous batteries in which the ' 'active material' ' is applied in the 

 form of paste. Realizing that this superiority was mainly due 

 to the relation of the molecules of the active material with each 

 other, and also their relation with those of the support part of 

 the electi-ode, I was led to make exjjeriments, the outcome of 

 which was a storage-battery, which I have patented. For the 

 sake of illusti-ating how the Plante form of battery is superior to 

 the pasted forms, I will suppose that a piece of wood represents 

 the support of the pasted plates, and that sawdust represents the 

 oxide which is to be applied to the support part of the electrode 

 in the form of a jpaste. The sawdust may be mixed with this, 

 that, or the other liquid, and made to adhere to the wood, to a 

 greater or more likely to a lesser extent. I immerse this wood 

 electrode, if I may be allowed to call it such, in sulphuric acid : 

 the sawdust will fall off in a comparatively short time, leaving 

 the wood support to a more gradual destruction. If the surface 

 of wood could be changed in some way so that it would resemble 

 sawdust, and yet in such a way that the molecules of this 

 changed surface preserve to a considerable extent their original 

 relation with each other (that is to say, their original atti'action 

 for each other) , and at the same time preserve their attraction 

 for the molecules of the unaltered portion, we would then have 

 a wood electrode (I apologize for the term) which would resem- 

 ble the lead electrode of Plante. Almost invariably, when the 

 pasted electrodes peel, they do so, not from the surface of the 



' 'active layer, ' ' but from the surface of the support metal. I 

 have experimented with but one Plante battery, which, by 

 the way, was the fii-st storage-battery that I ever made. This 

 battery was charged to its greatest possible capacity many times, 

 and also discharged suddenly, but the active layer has not peeled 

 from the non-oxidized portion of the lead plate. There has been 

 at times a falling of fine particles of peroxide, but no peeling 

 such as you get in pasted batteries. 



The sooner storage electricians recognize that the gi'eater the- 

 attraction of the molecules of a secondary electrode for each 

 other, the more durable will the electrode be, the better for all 

 concerned. Just as soon as storage electricians recognize the fact 

 that the quality of a storage-battery is to be judged, not by the 

 amount of peroxide the electrodes contain, but by the degree of 

 attraction which exists between the molecules of the active layer, 

 their experiments will be more fruitful, and the pasted plates of 

 to-day will be no more. The problem is not how to store 

 oxygen, but how to increase the alSnity of each molecule of an 

 oxide for its neighbor. Hoping that these remarks will set the 

 readers of Science a-thinking, and that they may have some 

 weight towards convincing them that all that is necessary in a 

 good storage-cell is molecular affinity, I close my communication 

 with great faith in the future of storage electricity. 



N. B. Aldeich. 



Fall River, Mass., March 18. 



INDUSTRIAL NOTES. 



Buffalo Blacksmith's Forge. 



Few progressive blacksmiths or metal-workers who look into 



the matter fail to acknowledge the superiority of the modern 



portable forge over the bellows and stationary blast-forge. By 



A NEW BLACKSMITH'S PORTABLE FORGE. 



the use of an improved portable forge, heat is produced more 

 quickly and with less labor and cost. The portable forge also 

 takes less space, while, so far as durability and reliability are 

 concerned, a comparison between the two is much to the dis- 

 advantage of the old style. The first co.st of the brick forge is 

 greater, and subsequent repairs and occasional movings make a 

 considerable item of expense, while repairs are seldom required 

 on an improved portable forge; and it may be moved from one 

 part of the shop to another with little ti'ouble. 



