ENGINEERING. 389 



The cars above alluded to are of the self-contained type, 

 in which. engine and car are combined. Apropos of this sub- 

 ject, which naturally provoked much discussion in the en- 

 gineering journals, t'he Railroad Gazette, whose professional 

 opinions are .entitled to high consideration, intimates that 

 the most rational solution of the steam street-car problem 

 will be found in a light steam-engine, which may be coupled 

 to and detached from the common street-cars as horses are. 

 This plan has been tried in several cities (Baltimore, Phila- 

 delphia, New Haven, Dubuque, Havana, etc.) with good re- 

 sults. It would admit of the use of the present cars, which 

 the self-contained steam-cars do not permit (and this fact, in- 

 cidentally remarked, is one of the most serious obstacles in 

 the way of introducing steam on the city railways, since the 

 substitution of specially constructed steam-cars would render 

 the present rolling stock, in which large capital is locked 

 up, practically valueless). An accident to either the car or 

 engine of one of these self-contained cars lays up the whole 

 apparatus for repairs; while an accident with the indepen- 

 dent system might lay up a car or an engine, but would leave 

 one or the other free for use, as the car could be coupled to 

 another engine, or the reverse. 



The subject also appears to have attracted an unusual 

 share of attention abroad, especially in England and France. 

 In Paris, for example, not less than thirty-live steam-motors 

 were in daily use about August last ; and new lines coming 

 to the very heart of the city were under construction, which 

 were to be operated by steam. It appears probable, there- 

 fore, that during the past year we have witnessed the ini- 

 tial steps of an innovation destined shortly to replace very 

 largely the old system of horse-power traffic in cities. 



THE PATENT MODEL SYSTEM. 

 A question which vitally concerns the inventors of the 

 country, and which has given rise to much discussion pro 

 and con, is the proposition to abolish the system, so long in 

 vogue, of demanding models of inventions to accompany 

 the application of the would-be patentee. The recent de- 

 struction by fire of a portion of the Patent-office building, in 

 which these models were stored, and the destruction of a 

 large number of them, gave the opportunity for the oppo- 



